Okay. A one hour walk isn't enough for a Border Collie. They need MUCH more stimulation than that. And it can, and mostly like is, contributing to her biting/scratching, destroying furniture etc. Sounds like a bored Border Collie to me!!
Are you using Stay and Wait interchangably? This will confuse her.
Stay means "Stay here until I come back no matter how long I'm gone"
Wait means "Wait here until I release you. It'll be quick"
If your dog is not staying when you give her the command/hand signal stay, you didn't teach it right. Most people give the command stay and expect their dog to stay in that spot, in the same position while they do something. And most of the time, the dog will leave his position because he has no idea what the word/hand signal means. In other words, he doesn't know what you want of him.
If you want to teach your dog to stay (and remember Border Collies pick up things quickly!), position yourself by the dog's left side. If you're using a clicker, click and treat, when she stays for even just a split of a second. Add a verbal cue/hand signal. Once you get a few repetitions in, take one step forward from your dog, if your dog stays, click and treat/praise/toy. Each time your dog stays move forward a step, and increase the duration of time your dog is staying. If she gets out of position, tell her to sit/lie down (which ever position you are working on), and go back to the previous step you took.
Repetition is the key. Remember, you want your dog to succeed! It's okay if your dog doesn't get it the first time. Don't be afraid to go back a step if your dog doesn't understand!
Show her how to do it? You mean you get on the ground and roll over, yourself? This will not teach your dog to roll over. Teaching this trick is very simple actually! And since your dog is a BC, she should pick it up pretty easily.
Okay, first off... What are you doing to teach her to roll over?