What was Paul Revere trying to do on his famous ride?

In all fairness the British were marching to seize arms, yet you're totally right, the ride was top secrete, a predecessor to the Culper Ring. No bells were rung, aside from Longfellow's poem. It was only William Dawes out of the three riders that actually got through without capture but "Listen my children & you shall hear the midnight ride of William Dawes" doesn't really work poetically