How to classify a footpath

Raw GPS traces usually have far too much noise to use as ways directly in OSM. You will need to trace over the track in an editor like iD or JOSM.

In order for routing software to be able to direct people along the path it will have to share common nodes with each on the paths or roads it joins with.

There are some tutorials here, but the iD (default) editor is user friendly enough that you may not need them.

In addition to other answers. If it is GPX trace that you have recorded while walking the path it would be useful if you also checked it's legal status by noticing if it has official footpath sign posts (designated) or it's local path that is well used (allowed) from local knowledge. It may have restrictions or be private. It's probably not good to map a path unless you walked it yourself and can add the status tagging. It is useful that you have uploaded the trace as ways mapped with using the average of multiple traces will be more accurate. Multiple trace are also useful for checking image background alignment.