For Visual Studio 2017 and Visual Studio 2019, the templates extension can be downloaded and install, either using Marketplace: https://marketplace.visualstudio.com/items?itemName=sdl.project-templates-for-trados-studio-2019 , either following the steps:

• In Visual Studio, from the menu select "Extensions" or from Tools -> "Extensions and Updates"
• Select Online and type inside the search area "Trados"
• Download the extension

• After extension is downloaded, close Visual Studio so process of installation will continue

• Click on "Modifiy" 

• Once the installation is done, you can open Visual Studio

• The creation of a new project using Trados Studio templates is now ready (you can use one of the searched template depending on the required implementation)

Note: The Github source code for Visual Studio templates extension, can be downloaded from here.