I've posted this in the past for potty training GSD's. This has worked for me with all of them but none better than with Lisl who is smarter than all of my other past GSD's.
This isn't the only method that will work, but it is what works for me and mine:
You have to take her out every 20 minutes when she is a very young pup. Stand with her or walk her around on a lead and tell her to "go potty!" Take her to the same place every time. You cannot go in once you've gone out to go potty until she goes. She must be made to understand what she is out there for. And you can't go out just when it is convenient for you. You must stick to a routine or she will never learn. No playing either. I never used treats, but you can try that too after she has gone potty.
Don't give into her using paper to eliminate on when the weather is bad, or cold, or windy. Suck it up and take her out. She won't mind the rain and they make umbrella's for humans.
Always lavish a lot of praise after she has taken care of business, and go right back inside afterward.
You must also take her out after:
Drinking (any amount, it takes seconds for them to go after a drink)
Pull her food no later than 1900 and water no later than 2000 depending upon your feeding schedule and how fast she eliminates. You will likely have to adjust this to work around your sleep/work schedule.
Crate her at night or have her sleep with you. You will have to get up several times so you may as well get used to it now until she can hold it through the night.
Take her out before bedtime, again at 0100, 0400, and whatever time you get up. The objective here is to make sure she is empty as possible before bedtime to eliminate the nocturnal trips as soon as possible after her little bladder can hold the remaining contents overnight.
German Shepherd Dogs are among the easiest of all breeds to successfully potty train. But you have to teach her. She can't figure out what you want unless you show her.
One other objective of this training is that they must be made to understand not only that outside is where we go potty, but that it is NEVER ever ever ever (except for an illness accident that you or she can't help) acceptable to go inside.
Bear, Anna, Molly, Ossie, and The Countess Lisl von Schlaf
An Unhappy German is a Sour Kraut!