How to pin a track to a map to retrace it later?

To “pin” the track to the main map to follow it, either use the tracks list: MENU > Tracks > swipe to the left on the track row and use “Pin to live map” option:

Or use “more” button in the track details window:

Pick “Pin to live map” and now you can follow the recorded previously track back or forward:

To “unpin” the track from the main map, hold your finger on a map until “map action” menu opens and use “Unpin track” action.

More on tracking:

how to see recorded tracks colored by speed or altitude