i have a 7mth german sheperd/husky mix and she just started her heat,i dont know anything about it

ive never had a female dog b4, let alone one in heat, i dont know anything about it. how long it lasts? how to prevent the mess all over my house? i want 1 little at least, when should i get my 3yrs male german sheperd and her together?, also wat are these doggie diapers i keep hearing about?, can she still do her business outside with them?wat about my evening walks?

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