Type Disk Cleanup into the search bar and then click on the shortcut to the app.
The utility will scan your system for files that can be deleted.
When it's finished the first sweep click Clean up system files and allow that process to run.
Scroll down until you see the entries for Previous Windows installation(s) and Temporary Windows installation files and click the checkbox to select these options (to free up the maximum amount of space check all the boxes, but be clear that you are deleting files NOT sending them to the Recycle Bin).
Click OK and then confirm you want the files deleted, and after that wait for the process to complete.
The files will now be deleted from your PC, a process that may take a few minutes.