Well, I would start with a lot of walking. Just walking, and walking on the bit, then stretched forward, then on the bit, then stetched forward.
Add backing up at a walk.
Add walking up hills and trotting.
Backing up hills.
Trotting a lot, and trotting ground poles.
Trotting cavalettie. Easy happy canters
Trot to canter trot to walk transitions and circles.
And? What makes you happy.