I am in the past. I have moved the cables. I have taken the gizmo from the table in the workshop. Now I have to find the office. Where is the office? If it is in the past, it is not in my game. Any help?

From the key slot (go back to the plank from the cables), go to through the door at building at left or ahead if you have the time travel key slot on your right.
Enter, forward and go through the door on the left.

Thanks MaG. What threw me off was that I do not see any desk. It justs looks like a bunch of rubbly rooms.

You're welcome. Enjoy the rest of the game.