Question

As you can see from the left I opened ROCS HARD DRIVE, then Rare Soul Sample folder, and the files on the right appear transparent I guess.. It won't let me open them at all.  Please help

Answer 1

I'm not sure if S1 supports MP3, however I'm pretty sure it does.

A similar thing happens to me with different file types. Try creating a new song, opening up the folder in another tab and drag/drop the file you want directly into S1. (Drag the file into the track page, not the main menu.)