Steps to return temporarily to a previous commit ( to check out a stale version of our code) and then come back to the latest commit.

Start with

git stash

to stash any uncommitted changes ( stashing saves your "not-ready-for-commit" changes in a stack : you don't lose them and afterward you can come back to them )

git log

to get the hash ( the long alphanumeric identifier) of the commit you are interested in

Once you have the hash, run

git checkout <commit-hash>

A "time machine" will bring your code back to the commit you selected.

.......

Check whatever you need in your code

.......

To come back to the "present", that is your latest commit, run

git checkout master  // it could also be a different branch

Lastly, to restore the "stashed" changes run

 git stash pop