Help with installing WADS on Wii

I am currently trying to download wiiware games to my console via SD card. I've read many things explaining the instructions, but I'm still confused on some parts.
1. Is installing a wiiware WAD different from installing a vc WAD? I have been able to download vc wads, but I just want to make sure.
2. What would Priiloader do? I need more details.