Hi, the first thing you need to do is find a cub near your location, then ask them about all the things that puzzle you at the moment.
Most clubs have a fleet of gliders that they 'hire out' to pilots. Obviously two seaters whilst you are learning with an instructor, then single seaters after you have gone solo.
I think that you need to qualify as a Basic Instructor before you can take passengers, unless the passenger a is qualified glider pilot.
As for taking club gliders off site, for a competition for example, this would be up to each club rules, if it was possible.