Is there a velcro backing plate on there at the moment? since its an orbital buffer/sander in sure there would be.
When purchasing lower end orbital you just need to take into mind that these are not built for paint correction use.
What these are good for is very light swirl removal and to enhance the paint. Can also be use to apply wax and sealants aswell.
If you want to go for more heavier correction then you will need a forced rotation dual action polisher. These start at around $600.00.
3M product saint bad but are more designed for the panel shop for quick and heavy polishing. Their compounds are pretty heavy which can remove upto 1200 grit sand marks. If you use this be sure to follow it up with the Finese It II finishing polish to remove the buffer trails left from the heavy compound.
In your case I would stick with Meguiars as their range is more suited to the enthusiast and there are more grades of polish to choose from.
To strip off old wax you should use Prepsolve (from Bunnings) or a 1:1 dilution of Ispropyl alcohol (aka IPA) and water. All you need to do is spray onto the surface let it sit for a few seconds then wipe it off.
This is the process that I usually follow.
wash, dewax, clay, rinse, polish (abrasive), IPA wipe down, sealant/wax app.
Hope this helps.