Hello Everyone that owns a dog!

I need some help. I will explain first what happened then if anyone could help me out with this, I would really appreciate it.
I found a puppy on the side of the road one day. When I found her, she was only a month old. I felt really bad and I couldn't just leave her there. I did post signs all over town and no one claimed her so we are keeping her. Which is good because I have fallen in love with her. She is great. Anywho, she is my first inside dog. I have cats in the house which they get along great. My big cat and her are best friends already. That's not the problem. heehee.
Ok, how do I potty train a dog??? I have never had an inside dog before and I have no idea how to potty train her. Give me a cat to potty train and I can do it but not a dog. I don't know if what I have tried is making it worse.
PLEASE!!!!!! Someone help me. I don't want to get rid of her and I don't want her to become an outside dog. I want her inside with me. She is a really great dog and she gets along great with my one cat and my kids. I was told if I don't get her potty trained and back in the house, then she has to go. She is outside for now because I work and she chews up everything, including my walls. So please, if anyone can help me, I would love it. I love my doggy and I want to keep her. Thanks in advance for any help or suggestions.
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Draconia, Dragon Queen