Hi Mark,
There is nothing too technical about floor sanding, however, it is never a good idea to experiment on a customer's floor.
Most hired equipment is harder to use without causing damage than professional. If you are determined and you are using a hired drum sander, start, with abrasive above the floor, move forward gently letting the head kiss the surface and at the end of the movement forward carefully caress the floor as you lift it away. You also need to careful with the edging sander which on its own doesn't go right into corners because if the pressure exerted using it is uneven it will certainly show when sealed.
The 3 grades of abrasive from most hire centres is just not enough to produce a professional job. The readily available sealants may not produce the best look and longest lasting finish that your client will expect. Oh yes, you also need a finishing sander which might be orbital or 3-headed depending on the type of wood and don't forget a triangular sander for the corners.
Going in without the correct kit is a bit like only owning a Numatic George and claiming you are a professional carpet cleaner.
Should you decide to sub-contract please don't be like one contractor who some month's ago had me sand one of his customer's floors. He keeps promising to pay.
Regards,
Keith