These radios are pretty simple to operate on.
Take the all the screws out of the case and pop the cover off, check that the 2 "zebra strips" are in place still. One will be in the case itself (usually) right above where the keypad buttons are, the other is larger (about 1 inch long) up towards the top above the display. 9/10 times they will stay in place but you need to make sure or you can cause some issues.
From there you are presented with a PCB with the button membranes and the LCD module, if you are just replacing the cover stop here. You just need to verify the parts above are where they should be and put the cover on, no ribbon cables or anything else.
If you need to tear it down further, 4 #00 Philips head screws on the PCB come out, then gently pull up on the LCD end to pop the connector on the back of it free. 2 more philips screws on the aluminum piece at the top and bottom and you can remove that as well.
That leaves you the main PCB itself, 2 screws on either end of the PA module towards the upper-middle and you can pull up on the board gently. Odds are it will be stuck very firmly to the gasket that competes the shielding on the bottom, it will take a bit of force, i use a plastic pry "stick" in the open gap at the top where you can see under the board into the bulging part of the aluminum case. CAREFUL! there is a SHORT ribbon cable connecting the knob set to the board, DON'T PULL on it, the way it sets in there makes it pretty darn easy to tear it right where it comes to the connector on the PCB, grip the large foam block on the backside of it and use that to pull straight out, from there you are pretty much done.
Assembly is the reverse of that, you can't really mix up wires or screws as they don't fit anywhere else. Only 2 "gotchas" i can think of are make sure you line the pins up properly on that knob ribbon cable and be careful putting the top LCD PCB back in as you can knock it off the board pretty easily by just bumping the plastic clips too hard.
For what it's worth, the main board from a 700p is physically identical to a 7100 except for the logic components, and you can swap them between chassis.
Hope that helps!!