Well, for the very basics you'll need a Homelite XL. You could also use a Homelite Super II, which has an aluminum body- harder to work with compared to the regular XL's plastic body, but sturdier.
Getting the handle off is pretty straight forward. I'd first completely disassemble the chainsaw first, the use the cutting tool of your choice to cut off the handle and a round hole in the back. I usually then cut off anything off the top that pokes up since there is that metal plate that gets attached to the top afterwards.
The trickiest part of the build I find is that small silver/aluminum piece on the left side. Its not an actual part to anything. I think It was a gas cap they found somewhere when they wanted to cover the Homelite sticker.
You can PM me with any specific question of a build.