A) this will void your warrantee(s)
B) Document every screw, etc that you remove
C) If there is any assembly/disassembly guide HP will have it as a PDF. Might only be available to HP certified technicians.
Look that up on Youtube - amazingly enough, there are a lot of how-to's on virtually all aspects of laptop repair. Some laptops are very easy and straight forward in disassembly/reassembly others (probably the ones Ram refers to) are complicated beyond belief. Hopefully, youtube will give you an idea of what you are dealing with. If you cannot find any videos for your exact model laptop, do not assume it is like any other.
Disassembling a laptop does not (as a rule) void any warranties, just like taking the cover off a tower does not void the warranty - if you damage anything (including stripping screws) or cannot properly re-assemble it, that will probably void the warranty.
For documenting (as Wysir recommends and I highly concur) I would highly suggest taking pictures after each set of screws or each cable is removed to aid in reassembly.
Hope it's of some help BUT: Do not disregard Ram's warning - if you do not know your way around a tower blindfolded, a laptop is not the place to learn.