Welcome and congats on the new RETFs.

It will take some time for them to acclimate to the new home.
Maintaining a stress free home is the goal.

Monitor the humidity and temps and let them settle in.
Sometimes mine sleep for what seems like days and you may find that a night light will cause them to shy away from becoming active at night.

Have plenty of places to perch up high also. The more pathways they have to move about the tank without being on the substrate the move you may see them move about.