Step-by-Step
Detailed step-by-step instructions for Bluebell CSL packages installation
Before you start...
Understand and accept the limitations implied by LiveTraffic's design approach...there won't be planes everywhere, especially not everywhere on the ground.
Verify requirements, it just won't work without.
For Windows, this includes making sure latest Visual C++ redistributables are installed. Download and install vc_redist.x64.exe.
For Linux users, who installed X-Plane from Steam, there are regularly trouble with different versions of the CURL library.
Windows only:
If LiveTraffic doesn't start and the only thing about LiveTraffic that Log.txt contains looks like
.../win_x64/LiveTraffic.xpl : Error Code = ### ...
then most likely you're missing vc_redist.x64.exe or it is not up-to-date.!
This page will then cover
LiveTraffic plugin installation (mandatory)
CSL Model installation (at east one package required)
LiveTraffic Archive
In the following, all actual actions are put into green boxes like below. Impatient readers may just want to skip to the next green box. The texts inbetween help validating the steps were successful and give background info. You want to read all text if you are new to the matter.
Download LiveTraffic.zip,
unzip the archive, and
move the LiveTraffic folder under your existing <X-Plane>/Resources/plugins folder.
This is what the folder structure should look like afterwards:

In the further course of the installation we will fill the .../LiveTraffic/Resources/CSL folder. You may have noticed the ShippedCSL folder, which contains a ground vehicle courtesy of X-CSL.
CSL Model Installation
CSL Models are models of those planes that LiveTraffic draws into the sky. So you need at least one of the following two possible packages. You could install both if you like. Beginners are recommended to start with the Bluebells. But the X-CSL models are available, too.
Bluebell CSL package by Oktalist
With the recent (31-AUG-2020) release 1.3 the installation got a bit easier:
The Bluebell CSL package installation comprises of 12 files if downloaded as ZIP from Oktalist's Google Drive, which is recommended and the basis for the following description:

If you prefer X-Plane.org then there are the same files available.
Download all 12 .zip files from the Google Drive location
Select all rows (e.g. using [Ctrl+A])
right-click, select Download from the popup-menu
Google Drive creates a new archive with those 12 ZIP files, which takes a while, before the download starts. In the end you are downloaded nearly 650 MB
You end up with a
drive-download*.zip. Unzip that so that you get the 12BB_*.zipfiles.
Move all 12 .zip files to a directory under LiveTraffic/Resources, e.g. the already existing one,
.../LiveTraffic/Resources/CSL
Unpack each of the 12 .zip files, which each creates a folder, which in turn include the CSL models and some supporting files.
Remove the .zip files after extraction.
Note that BB_Airbus1.zip and BB_Airbus2.zip both contain a folder BB_Airbus, and BB_Boeing1/2/3.zip all contain a folder BB_Boeing. Depending on how your ZIP tool handles this you either end up
in just one
BB_Airbusfolder and oneBB_Boeingfolder, and the unzipper asking if you want to overwritexsb_aircraft.txtandCredits.txt(say yes, all overwriting versions are equal), and you are done already,or the unzipper tool creates separate folders to avoid any overwrites. In that case you need to merge all
BB_Airbus*folders and allBB_Boeing*folders yourself (and again: all Airbus versions ofxsb_aircraft.txtare identical as are all Boeing versions). This might for example looks like this:

In the end, you should have a folder structure like this (only some folders are opened in this screenshot an example):

Fire up X-Plane and
check LiveTraffic's Status/About page's line "Number of available CSL Models": It should not show warnings but instead a high number: That's the number of models successfully loaded;
go to any busy airport (check coverage), wait till 90 seconds after the scenery has loaded, and LiveTraffic should display the first aircraft.
You see aircraft? Great! Check out the Aircraft List to see where they are, hit the
Camera button to hop on any plane's tail and see it up close.
To be really sure that your installation is correct and free of errors:
Quit X-Plane and open the Log.txt file from X-Plane's main directory in any text editor. Search for "Bluebell"
You should see about the following in your log. If so, everything's right:
If you don't see any of the INFO lines shown above then your logging level is too low. Go to the Advanced Settings and increase Log.txt logging Level to at least "INFO". Then start up X-Plane once again to re-produce the INFO log lines.
And now go ahead and do your
First StepsIf you require more help and support check for ways here:
FAQHelp, Support, Bugs, IssueX-CSL
The X-CSL package comes with an installer, which makes installation a breeze:
Create a target directory where the X-CSL models shall be installed, e.g.
.../LiveTraffic/Resources/X-CSLGo to the X-CSL Download page and download the latest client. It doesn't matter which one you choose (at the time of writing there was one for X-IvAp and one for Altitude), generally, prefer the updater with the highest version number.
Install the updater somewhere according to their instructions, then start the X-CSL-Updater.
The X-CSL-Updater will not recognize LiveTraffic as a target. You have to tell the updater the specific installation location:
From the updater's menu select "Set Custom Path".
Confirm the warning regarding advanced usage.
Select the folder you created in the first step.
Done correctly, the Custom Path should now be displayed in the main window:

Click the [Index] button: X-CSL Updater will download available models and present them in a list.
From that list you can pick the models you want to install. Multi-selection possible, [Ctrl+A] selects all.
Finally, click [Update] to actually download the models.
You can re-execute the X-CSL Updater any time to add more models or update existing ones to latest versions.
You might need to tell LiveTraffic where you installed the models. Add the path to the CSL Package Paths if it is not below an already configured one, for example like this:

Individual CSL Models
You may find individual CSL models on the internet. For example, there is a CSL Download section on X-Plane.org. A CSL archive contains several files in a folder structure.
Once only:
Create one folder, which is to collect all those individual CSL models, e.g.
LiveTraffic/Resources/OtherAdd this collective folder to LiveTraffic's list of CSL paths, see Settings > CSL > CSL Package Paths. As LiveTraffic searches up to 5 folder levels deep it is sufficient to add just this one top-level path and everything underneath will be found, too.
For each new model:
unpack the ZIP archive that you downloaded,
move the entire folder of the new model unter the collective folder, and
restart LiveTraffic (or all of X-Plane) as new models in existing CSL Packages are loaded on startup only.
This may then, for example, look like this:

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