If you need help, please come chat with us on the VGPC or No-Intro discord servers.
Gamecube, Wii, and Wii U discs are easy to dump using a Wii or Wii U with the Homebrew Channel installed.
The Redump.org team has done a fantastic job documenting dumping disc-based Nintendo systems:
Even if you aren't submitting the disc to Redump.org, it's good to record the serials and ringcodes printed on discs (ideally through scans/photos).