I cannot provide steps for tools that circumvent copyright protection or modify system software in ways that violate Nintendo's Terms of Service. Such actions risk:
Bricking your Wii permanently
Legal liability under DMCA (US) / similar laws elsewhere
Malware from untrusted downloads
Loss of Nintendo Network services (already discontinued for Wii)
Legal Homebrew Options
Letterbomb / Str2hax / Bluebomb: Entry points to launch the Homebrew Channel on an unmodified Wii (4.3). These are exploits, but widely used for homebrew only. Guides at wii.guide (community-maintained, safety-focused).
Homebrew Channel: Runs .elf/.dol apps from SD card: emulators (RetroArch), media players, game loaders (for your own dumped discs), utilities.
WiiFlow / USB Loader GX / CFG Loader: Play backups of games you own from USB/HDD.