They're unlikely to be out of alignment unless something is seriously out of whack with the camera - they're just glued to a shaped block.
The front panel is just clipped on - one little catch type of feature in the middle of each of the long sides, like this...
A bit of a press on the side of the camera body next to the catch can help with easing the panel off...
You don't need to get both catches released - getting one cleared is enough to get the panel tilted up at one side, after which it can just be lifted away.
Once it's off, you have access to the insides of the lenses in the viewfinders, and the mirrors...
The mirrors look like they're silvered on the exposed surface, so clean with care to avoid damaging the silvering - blower brush to remove the loose crap, then something like a microfibre cloth wetted with lens cleaner to remove more stubborn bits. Don't expect to get them perfectly clean - better to have a few bits of crud than no silvering. The lens are plain, uncoated glass, so give them a good clean inside and out.
If either of the mirrors are loose, you'll need to stick them back in. Remove any dusty crap from both surfaces and use the minimum amount of glue needed to hold them in place. That way, there's a better chance of being able to remove them again later. I'd probably try with thin double-sided tape first (just a thin strip at one end - not over the whole area of the mirror).
When done, just ease the front panel back into place until it clicks.
