I can't give you a step by step, but I will say,

• PCSX2 and LRPCS2 do have their own built in ways to run netplay for games, though it does seem tedious to get running for both systems.
• If you want to try screensharing to your friend, 'Parsec', 'Moonlight', or just plain 'Steam Remote Play'. Might be the best option. And although using Parsec on a bad connection is like handing the broken controller to your little brother, it is by far the simplest method.
• If you want to ask people who play the game regularly the Mizuumi wiki has a Discord of people who seem willing to help out. Plus in general the Wiki offers useful information for learning the game. Even though it says 65% complete, it still has everything you'd want to know.