When you setup Unreal Engine through the Epic Games launcher a file association is setup to allow tools to find your engine install, and enable some shell menu items when you right click on a uproject file.
This isn’t setup by default when you build from source, but it’s really easy to do.
First setup the file association by running
UnrealVersionSelector.exe /fileassociations from within your engine binaries folder (note the name may be slightly different depending on your platform). This will register the
.uproject file type with the engine and allow you to launch the editor by double clicking on the file.
Then you can also run
UnrealVersionSelector.exe without any extensions to register your engine install.
These steps will set the path to you engine install in the registry and allow other tools like Rider to find them later on.