Read more. Try Good Owners, Great Dogs by Brian Kilcommons.
Not long.
Basically; exercise, exercise, exercise. A hundred sits a day. Rewards and gentle praise (don't over do it) for good behavior.
There is dramas around doors. Avoid confrontations or meeting other animals and people near them.
A big, open, new to her space like Lowe's is scary first time for an adjusted dog.
A good obedience trainer may help. Dogs are comfortable being controlled.Heel, sit, heel, sit, stay.
And it takes time and commitment. Our last rescue was a puppy mill mom raised in a back yard in a cage stacked with cages of other dogs, outside.
It took a year to get her where she wouldn't wake up defensively growling and biting if you touched her. She is fine now.
Good luck,, keep us posted.