Here are a couple of YouTube Videos:
https://www.youtube.com/watch?v=NKKeQUeo4iI

https://www.youtube.com/watch?v=1Eve6e8epKQ

You don't really need to disassemble the bike all the way. You can pull out the seat post and get a lot of the bike right there.

You can also remove the bolts/screws for such things as the water bottle cages and spray into them.

Sometimes you can get to the seat stays and chain stays though little drain hole that might be near the rear dropouts. Same goes for the front forks. Just make sure to use a wire to unblock these drain holes a couple of days later after the corrosion prevention material has dried some.