Hi! I'm Paughco (call sign on MP). I fly with the A2A Misfit Squadron, usually on Fridays and Sundays. Some time back I wrote up a post on how to get set up in MP and how I normally get my setup and airplane ready for a typical MP flight. Here is the procedure again:
We use the "DigitalThemePark" server on JoinFS. Here is a link to the web site:
http://pmem.uk/joinfs/. Click on "About," "Install," and "Manual" to get the instructions on how to download, install, and operate. It's pretty easy.
Next, we use "Discord" for communication. This is another free download. Here is the link:
https://discordapp.com/. More stuff to read, download, install, etc. You need to establish a logon ID, password, etc. I use the same stuff for Discord as I have for this A2A forum. Then you have to log on to Discord and navigate to the "A2A Community." I've got a Discord shortcut on my desktop, and when I double click on it, it opens a window that is connected to the A2A Community. There's a spot where you can click to join a voice channel. We usually use "MP Flying Chat 1."
NOTE: You need to be "let in" to the A2A Discord by Lewis. Find one of Lewis's posts on this forum. Then contact him via any one of the links on his signature block, or by a PM on the A2A Forum.
I recommend that you try the steps described below some time other than just before you want to join a Sunday flight!

That way you can fool around, read the manuals, fool around some more, etc.
Here is the typical sequence I go through in getting ready for a MP flight:
1) Put on headset.
2) Open Discord, click on MP Flying Chat 1. Unfold, then tap the boom mic to see if the little green circle come on showing that my mic is live. Fold it back in.
3) Open JoinFS, click on View, Hubs, and check that I'm joined up with "DigitalThemePark." (I've got it set to autojoin DigitalThemePark, but I check anyway).
4) If we've agreed to use real weather, open up Active Sky. If not, omit this step and use "Fair" or "Clear" default weather.
5) Open P3D (or FSX, whatever) and load the agreed upon aircraft and starting field.
Steps 1 through 5 take all of about five minutes, not counting the time it takes for P3D to load, but typically on a fly day I start about a half hour before our planned takeoff time. Once there, I prepare the aircraft, start it up, let it warm up a bit, then maybe do a mag check, etc. About that time folks start to arrive. Chit chat ensues while we discuss the flight ahead, and wait for others to show up. We try to take off on time.
I ask the rest of you guys to add any comments that may be helpful. It would be cool if we could eventually have a sticky with a concise description of how to set up and use MP for our flights.
Thank you
ATB