You don't want to remove the intake manifold as you only want to redo the covers. The steps are straight foreward:
1. intake ruber hoses that connect to airboxes
2. hoses and wiring attached to throttle bodies
3. throttle bodies
4. sensor on top of manifold
5. remove bolts from cover.
On the last step I can only guess that the bults on the outside of the covers are placed from the underside of the intake manifold. I cannot see them from the top. All the others are reacheable from the top.
When putting all together you may think about the gaskets. The cover gaskets usually are fine of not damaged during removal but I'd change the gaskets from the throttle bodies.