Hi, the files need to be in .ogg format. You can convert them in Audacity, or there's plenty of online converters.
Oh, hah, I guess it depends what version we're talking about. I can't help much with Mk III and V, as they weren't designed for custom wavs. However, there was a discussion at https://www.reddit.com/r/Vinesauce/comments/66koho/is_there_a_link_to_the_text_t... that might help. Each sample needs to be 16-bit mono and a particular sample rate.