OsmAnd: How do I use it to edit maps, and how do I upload a track?

So I am attempting to use OsmAnd.

I’ve got a walking trace of a new footpath near the new Walmart.

But …

Well, it goes from the bike path to the Walmart. (Actually goes from a section of parking next to the bike trail – different from the normal Walmart parking lot – up the hill to Walmart).

Problem number 1: It doesn’t actually match. The phone’s GPS location does not match up to the bike path. In fact, the phone’s GPS disagrees significantly with where the map claims the bike path is – about 80 feet.

I’m not sure how to put satellite images up against the OsmAnd background. For that matter, I seem to have forgotten how to get them on the background on the website as well.

On the osm.org website: the aerial imagery is only available in edit mode.