Painting on canvas

[sparkler]

Hi all!
I recently bought some canvas already attached to the wood and everything, now I've never painted anything before but thought I'd have a go. When I was looking for some tips online though I kept coming across the point that it has to be prepared, the leaflet that came with the canvas says PRIMED on it, does this mean it has already been prepared or do I have to do something else to it before I paint on it?
(sorry about going around the houses in the question, I always do that! lol )