Please don't flame me there is a ton to read on this site and I'm a bit confused

I have hbc on wii 4.0u. I also put some apps on the SD card and I'm seeing them in HBC.

Some of my questions:

1. Do I need to downgrade from 4.0u to install wad games? All the downgrades I've seen require twilight hack...

2. Can someone send me a known safe wad? Maybe punch out? (or anything else) I'm also worried about downloading an unsafe wad and bricking my sys.

3. I want some free games lol

Thanks for any help anyone can give I'm pretty noobish at this