After you download the latest release (from just 2 days ago) from here:
https://github.com/Aurelio92/RVLoader/releases
The app you open from the homebrew launcher is
RVLoader, not BBLoader.
You can check the
installation instructions here (I copied them below):
Basically, after this is done, RVLoader will boot (and anytime you boot your wii, RVLoader will boot). While in RVLoader, select a game, and press button B, that will propmt you with that game options, like activating GC2Wii and setting it up (connected extensions, sideways or normal, and button per button settings). Just fill everything, press START to save, and done. Start playing. Tested it so far on New Super Mario Bros. and both Mario Galaxy, it's been working great.