In British English, forwards is the everyday way of saying “towards the front”: you walk forwards, lean forwards, pass the ball forwards. Americans usually write the same idea as forward, with no s. The extra s is not a plural. It is an old adverb ending — the same little -s you meet on towards, backwards, and afterwards — and it only marks “in that direction.” You also use it for time and for progress: from that day forwards; the work is moving forwards. Though actually, even in Britain the two spellings sit side by side, and nobody is lost. Careful writers still prefer forward when the word is an adjective (a forward plan, a forward-looking idea); the s-form is happiest as an adverb. One trap that looks the same: in sport, the forwards are the attacking players — that s really is a plural of the noun forward, a different story from the adverb.