Hello, I have recently become a proud owner of Piper, a Maltese x Shih Tzu. She is 7 weeks old. I am currently toilet training her both inside & out, but of course inside is becoming a struggle, puppy mats don't seem to be working. As I am new to all this puppy hype, I'm keen to know what exactly is a crate and and it's benefits? Where can I purchase one?