two ways to hack vwii.
Hacking through wiiu mode, aka wuphax, no additional game required
Hacking in vwii mode. Letterbomb exploit was patched, (the one wii uses) So you need to use a exploit similar or like smash stack, requires a copy of brawl.
Wiiu mode has a 1 primary entry point, and secondary entry point, aka a entry point that needs a primary one.
Primary exploit is through wiiu browser, unstable.
secondary exploit, known as haxchi and it's "colboot" variant, coldboothax, can be installed via web browser exploit. Requires a compatible ds vc game, and it must be a be a legit purchase, no piracy, and is highly recommended.
Honestly, since you start in wiiu mode, just hack wiiu mode first and install haxchi or coldboothax. Then install wuphax, go to vwii and install hbc