Gen 2 changing sprites

Hi everyone.
I REALLY wanted to put Latios and Latias in pokemon Crystal, i already have the front and back sprites, but i have no prior experience to rom hacking. Could anyone give me some instructions on doing this?
unfortunately i couldn't find many tutorials for gen 2. I've heard of the pokecrystal disassembly but it seems so complicated and i'm not familiar with any of that stuff. Why does hacking Crystal have to be so complicated? :(
Anyway, if anyone could help me with doing this would be greatly appreciated. Thanks in advance.

You can find a list of tools at HackRomTools. If that page doesn't have what you need, there's also a GameBoy tools page.