Lola, Rhinestones are applied with a kind of soldering iron or a heat press. With the applicator 'wand' type you pick up each stone with the hot iron and then press it to the garment. They are quite durable when properly applied. You can also buy pre-made designs made with rhinestones. I bought an applicator to try it out but haven't used it yet apart from playing with it. It seemed very fiddly but could be good for bespoke garments.
The best thing to do is to go to YouTube and search 'Rhinestone' or 'Rhinestone Application'. You'll get lots of visuals there including a whole rhinestone system from Ryonet. There are all kinds and colours of rhinestones including studs.