Hi ,
Your game project will not be included in the Engine’s solution. However, once you have switched the game project to use your source code version of the Editor, when you open the solution for the game project, you will notice that it now includes the UE4 source code as well. When you open the game project itself by double-clicking on the .uproject file, it will use the binaries that were created when you built the Engine using the source code.
If you were to switch your project back to using the binary version of the Engine from the Launcher, the source code will no longer be available in the game project’s solution, and opening the game project will now use the Engine installed by the Launcher.
One thing you may want to keep in mind once you start working in game projects using the Engine built from source is that since it includes the source code in the solution, building or debugging the solution means you will be building the Engine in addition to your game project. If you do not already do so, it may be a good idea to build or debug by right-clicking on your game project in Visual Studio and selecting the appropriate option from the context menu. Build times have already been reduced significantly since the Engine was launched, but you will still save a little time by doing this.