For this achievement you simply need to sleep for 10 days and you will get the achievement:
You can earn all the achievements for surviving simply by sleeping your way to 50 days.
you can keep track of the days using your (GPS TRACKER).
Note: (This achievement seems to be bugged for some players so if you dont get the achievements try relogging. If that doesnt work try creating a new game and sleeping for 50 days again)