Here's a link to the files to print:
https://bitbuilt.net/forums/index.php?threads/g-wii-cad-files.2319/
As for a guide... well, there are worklogs, but every (almost) portable which is built does not use a guide. (Looking at worklogs and some youtube videos help) Meanwhile, though, I
do like to look through the G-boy manual sometimes. Even though it is outdated, it simplifies some things (such as where to solder on the Wii motherboard for things such as Audio/Video). You can find this by clicking "Manuals" in the screen above.
And, of course, don't forget to look at the Definitive Wii Trimming Guide and other relocations and solder points too!
And there are some Louii workvideos from
@GingerOfOz which is pretty up-to-date. (Not a G-Wii, but still good to watch for learning)
And, of course, please do self-studying, too...