The literal translation of "s'il vous plait" is "if it pleases you". It's just how you say please in French. Another less formal way would be the tu form -- "s'il te plait". "Plait" is the verb and cannot stand alone without a subject or an implied subject as with commands -- "Boit le vin".

"S'il vous plaît," taken together as a phrase, is the French way of saying "please." You'll sometimes see it abbreviated in informal writing as SVP. You can't just use "plaît" on its own to mean please, though you can use it in other contexts. ("Elle me plaît" means "she pleases me," for example.)

Ah got it, merci beaucoup :)