Here’s a quick break down:

dsquery computer –inactive 8 –limit 1000
This line searches the AD for computers that have not logged in for 8 weeks or more. By default the dsquery will only look for 100 objects so we need to raise the limit.

$comp -replace ‘”‘, ”

Here we are cutting the “ character that dsquery hands the objects names over with. These are located at the start and end.

Disable-ADObject and Move-ADObject are self explanatory.
Note they do have –whatif switches that will help if you want to see whats going to happen.
Append -whatif to the end of the command.