The salsa is a dance  which respects basic steps, which dances generally for two, where the boy guides the girl (sometimes badly interpreted as a shape of male chauvinism), but where we can have a practice also only, or in some: on-line (comparsa, suelta salsa), in several couples (rueda of casino), or another leader and two partners (more rarely two leaders and a partner) etc...

We distinguish, among the multiple manners to dance the salsa, 3 main styles:

The Cuban style (dance called casino in Cuba), most usually practised in France, because of the strong Cuban Diaspora living there and passing on its culture. Dancing schools teach essentially this style, maybe easier to land for the physical sensation of the European.
The salsa itself, improperly called "Puerto Rican" in France, style the most running in the world, the characteristic of which is to respect a line of dance.