I use an Elgato to connect my switch to OBS. Took me a solid week to get everything set up correctly. Once you figure OBS out its not too difficult though. There is a learning curve of just getting used to using it and learning all the options. If you have any specific questions I'm happy to help
What system do you want to stream? Pc, xbox, ps4, or switch?
I havent tried putting my pc on two monitors to stream through it, but I'm sure its possible. I use a laptop though and its easier with a more powerful desktop.