Prebuilt binaries for BuildXL are only distributed internally within Microsoft. Externally you'll need to build the project locally from the main branch of its repo. See the Developer Guide for instructions.
DScript Visual Studio Code Plug-in
You can find the plugin in the marketplace under "BuildXL". It should be recommended for our repo.
The steps to take are:
This plugin enables C# and C++ target language support for building using BuildXL in Visual Studio. It is meant to be used in conjunction with the command line bxl -vs command that generates .g.csproj and .g.vcxproj files from DScript build specs.
You can build it locally with this command: bxl out\bin\debug\ide\*. And find the resulting file will be dropped at: out\bin\debug\ide\BuildXL.vs.vsix. You can install it by simply running the vsix.
If you see a message like this: The application which this project type is based on was not found. Please try this link for further information: http://go.microsoft.com/fwlink/?LinkID=299083&projecttype=DABA23A1-650F-4EAB-AC72-A2AF90E10E37 then you need to build and install the plugin. This is the plugin's GUID which is referenced from the generated proj files from bxl -vs.