how do you melee in holdfast

left click to attack, right click to block once you've got the bayonet or sword out, but check settings > controls in case yours got rebound. the timing thing: don't sit in block the whole fight. block as soon as you see their swing start, then hit straight after it lands on your block. swinging first into someone who's already blocking is how you die every time. and fix bayonet before you charge, people forget that constantly.