The fundamental thing that you have to remember is,

Brush twice a day & floss once a day

People ask me which teeth do I floss: I only floss my front teeth because I can’t get on to my back teeth. Well, if you can get on with your food and fork on your back teeth to chew them, you should be able to floss them too because obviously we floss the teeth that we need to keep, so you decide which teeth you need to keep and you floss.