[My baby*Fergie*]

Hello everyone! ...I have had Fergie now for like 5 weeks now...and I am having an issue on how to bath her properly...and on what products to use...I live in Canada in a small town with only a few local pet stores. I have been using a tearless puppy shampoo and a spray in conditioner. But what confuses me is how easily her hair looks dirty...but her skin seems dry.It looks like dandruff. So I bought some tea tree oil ointment for her...and am thinking of delaying her next wash. But what confuses me is how can her hair look soo oily if her skin is so dry?? am I washing her wrong?? I really dont know if i am doing everything right?? I need all the help I can get lol I would appreciate any advise!!! thankyou !!!!!