Basically, a couple of rag-tag French battalions set off to Bristol but rocked up near Fishguard due to adverse weather (the original plan was to invade Ireland, Bristol was meant to be a diversionary raid, to pull away the English fleet from Ireland). In the Fishguard area they looted a few villages, found barrels of wine from a recently wrecked Portuguese ship, got pissed, fell asleep and were easily subdued by local soldiers and residents. It’s comprehensively explained in this very watchable clip:
