Welcome to
GPC! This is a great site to get a lot of information. Just cruise around and don't let it get to overwhelming. I would suggest adopting as there are many in need of homes.
You should get two as well. They are happier in pairs. Rescues will usually only adopt out in pairs as well especially if you don't already have one.
Check out the cage size recommendations and also the diet and nutrition section. There is a sticky in the nutrition section with veggie charts on how often to feed certain veggies. It's a great resource.