Is it the whole stack, tuner, amp and cassette deck?
If you haven't done it before, take a lot of photos, you'll forget what goes where. I use one of those blue silicone mats for my work space and painters tape that I put all the parts on while taking apart. That way I know the correct way to put back together.
I'd also have a bag of Q-tips or better yet, the foam versions, and a bottle of IPA to clean everything. If you see any black tar like goo, use a magnifying glass to make sure you get all of it out, it might take an hour or two but those gooey pieces will slow down the tape if left behind, good luck with the repairs.