Hang in there, Bob. You'll get it. Most editors are quite forgiving (at least during the learning curve), so do the best you can and let 'er rip. And if you have more questions we'll try to help.
The key information is (a) what song are you submitting a cover of, (b) who is the performer of the cover you are submitting, (c) what is the title of the performance (sometimes titles vary from version to version, even if it's the same song), (d) what's the name of the "release" (the "record" your cover is on -- the name of the album, for example), (e) what date was the release released (we want the earliest release), and (e) what's the label name. Important additional information is the catalog number, if you can find it. Biographical information is welcomed but not essential. A youtube clip is very welcome. If you have additional information that doesn't fit comfortably on the form, include it in the text box (at the bottom of the form, where it asks for references supporting your submission). The idea is to provide enough information, and back-up references for that information, to demonstrate the accuracy of your cover submission information. (The editors need to confirm the accuracy of your submission. Try to make their jobs as easy as you can.)
You should routinely check to be sure (a) the song being covered is actually in the data base (query the name of the song), (b) that the cover you want to submit hasn't already been submitted (check the "versions" list against your proposed submission), and (c) whether the release your cover is on is already in the data base (check under the list of releases already identified as being by the artist/performer your cover is by). I typically open two SHS screens, one for the submission form and the other for checking the data base against the data I'm submitting.
This is all simpler than it may sound and I'm pretty sure you'll get used to it pretty easily.