You will need a pilot book to make the entrance. There is a fairly strict tidal window and a right angle dog at the entrance (at least there was four years ago when I last went).
You can either tie up to the town quay ( I managed on a mid summer weekend without rafting) or pick up a buoy. The town quay and most of the nearby buoys dry.
There is a sailing club towards the seaward end of the quay which has showers ( and a bar) and welcomes visiting yachtsmen.
I think there is a yard further back along the town quay.
Entry 2 hours either side of HW, unless you can dry upright don't go alongside the quay.
HM will advise which buoys to pick up, alternatively contact local RNLI cox - they've got the big boat in there.
I'd suggest Aberdyfi is easier to get into (contrary to the pilots' haverings), far prettier and less trippery. There are two visitor buoys at the beginning of the moorings which are good for 2.5m draught.
Both are half-tide harbours and not for entry in heavy onshore weather.
Pwllheli is the only all-weather, all-tide harbour in Cardigan Bay.