How are we meant to play online when there isn’t a server browser?
A server browser has been confirmed to be in development, but there is no eta on when it’s going to be completed and released
Essentially you should be able to find people online via various websites and friend them, from there you can invite each other to games. I would recommend looking for a spartan company that specifically plays H5PC or even check and ask around here, reddit, or other Halo based websites.