I'm finishing playing heart gold and soon will be playing black 2, I don't understand natures or what sweepers or tanks or anything like that is. All I know is I'd like to use bulbasaur, squirtle, charmander, pikachu, and abra. I'll probably evolve them and have already caught them in heart gold, However I don't know if they have the best natures available to them and if I need to breed them again in order to get the right ones I can.
If you could help me understand what natures to get these pokemon and how to make them sweepers or tanks or whatever that means I'd really appreciate it. Also what should my 6th pokemon be?
Thank you! Please help!