If you got on to the lobby you're most of the way there, final check would probably be to make sure you're using both the right version of the EXE (either the most current nightly, or the most current stable release, realistically) and that you definitely have port 7808 open if you want to host or host on stand alones servers (meaning; joining a server with 0 players to 'start' a game).
Playing times are a tiny bit random, you may find games in the week, you may not. You will most probably find games on the EU evening-early morning time period, and most especially on fridays and saturdays.
I've been ridiculously busy with real life(tm) the last couple months so I haven't been around enough to even know the true answer to that question right now, but multi is at the quietest it's been since I returned to these forums (4 years?), hoping there will be new life at some point, you may be able to muster people up to play with via a forum thread or on #hard-light on irc. There are people out there who want to play at least semi-regularly, trust me.