I try different polishing system for concrete and natural stone --- even used diamond brushes from diamabrush --- only did not have money to buy the planetary system that I believe will be the best for the restoration job.
You can only skip the starting grit for example if the floors do not have deep scratches then you can skip the grinding up to 400 grit but the next grits should never be skip already or you will never achieve the shine that you expect. Also some videos seems that it is just easy... believe every floor that you will be doing is not the same in the video --- practice, patience will be needed in polishing concrete and natural stone.