I'm no expert, but I'm just getting my 4 month old used to grooming etc.
Try tiring her out before you groom her or start training. As you can't take her out yet, sit on the floor and get her to run around you chasing after a toy. That's how I tire Dexter out, plus it's great arm exercise!
If you want to be able to get her on her back, after play let her nap on you and roll her over and ruffle her belly/chest. She'll get used to the action and to be touched on her underside as well
Hope that helps!