How to launch a specific project from Visual Studio solution

You can configure a solution to have multiple startup projects - Right click the solution in Solution Explorer, choose "Set StartUp projects", choose "Multiple Startup Projects", and choose the ones you wish to have start. They'll all be started when you hit F5.

Or, you can right click any project in Solution Explorer, and choose "Debug"->"Start New Instance" or "Debug"->"Step Into New Instance" - you can do this to any projects you want to, at any time. (So, if you want to have some projects start when you start debugging, and start others at a later point, this is the way to go)

Right click your solution and choose "set startup projects"

next, you can choose which projects you want to start simultaniously

or you could right click a project and set that one to startup, each time you "F5", that one will start. You can verify which one is set as startup by looking at the one in bold.