

My sister just adopted a three year old aussie collie mix from the shelter today. She is the sweetest girl ever, super calm and extremely intelligent. So far she seems to be settling in well.
Anyways my question is where do you even start on training her? She seems to be potty trained because we had her in our basement and she was chugging water but didn't go pee until we brought her outside. She somewhat knows sit, she's not great at holding it though, and she has shake perfected. So how did you train your aussies? What commands did you start with and what are the most important ones for her to learn right away? Also what supplies/collars/ leashes/treats do/did you use when training your aussies?
Finally we've noticed that she seems very scared around my dad. She was fine with him before when she was outside but when we brought her in the basement she got scared and started to growl and bark at him. She did the same to my brother but he got her to calm down and once he started petting her she was totally fine. Any ideas on what this could be? Thanks!