Some meets are drives, some are more 'stationary'.
Generally, there's a location and a time to be there, e.g. a car park. For a driving meet, you stand and have a chat for a bit until everyone's turned up and then everyone convoys out along the route. Often there's a few stops to work out what's next.
(thanks shifty!)
A park-up meet is exactly that, park up next to everyone else (if you're first, pick somewhere close to the entrance and with plenty of space either side), have a chat with everyone, take pics, have a meal, get ideas e.t.c.
If the meet's quite far away from you, but there's a few local people going, you can always convoy to the meet.