While the current round continues resolving, plot your return: When the next round starts, program your registers as usual, but without putting your robot on the board yet. You will choose the direction your robot faces when you return, so keep that in mind as you program. Other robots could also be coming back onto the board at the same time as your robot; keep that in mind as well!
When your priority comes up during Register 1, place your robot onto the Reboot Token that is on the same board where your robot fell into a pit or fell off the board. If your robot fell off the Docking Bay, they Reboot at their Archive Token there. Choose your facing (ignore the arrow on the token), then resolve your Register 1 programming card as usual.
If your reentry space is occupied by another robot when your priority comes up during Register 1, move the obstructing robot 1 space in the direction of the arrow on the Reboot Token or on your Archive Token. Then, place your robot onto the Reboot space facing in the direction of your choice. In both cases, moving an obstructing robot does not count as your robot “pushing” that robot.