That's a very simple "script" to be executed in LINQPad. It show number of hours the computer was on recently. It uses event logs to get that information based on sleep/wake-up events.
Easy way: just copy TimeTracker.linq to <MyDocuments>\LINQPad Queries. It will be automatically picked up by LINQPad.
Advanced way: For development purposes it's better to clone the repo to a folder and make a symbolic link to that file:
git clone <this_repo_url>
cd "<MyDocuments>\LINQPad Queries"
mklink TimeTracker.linq <path_to_repo>\TimeTracker.linq
Do the same in F#. It's a bit of a playground for functional approach so F# would suit better.