you *should* be able to click "raw" on ap-subscore-cheeser.user.js
below and it show an install screen.
if not, select all the content, go to the tampermonkey dashboard (click the icon in the top right, might be in the puzzle piece menu; then click "Dashboard"), then go to the "+" tab on the dashboard, paste in the script (replace everything already there), and ctrl/cmd + s to save, then reload the scores page