Extract the archive and paste it on your SD Card 1 under CFW/Retroarch/.retroarch/overlay

There are also some random scanlines I've found online included, if you wish to try them out.

Make sure that On-Screen Overlay > Display Overlay is toggled ON and then select the appropriate overlay under Overlay Preset.

Make sure that Keep Aspect Ratio is enabled under Setting > Video, but Integer Scaling should be turned off.

I hope you enjoy it!