If you park in the main National Trust Rumps Point Car Park at the disused lead mine tips and take the outside path, marked in red, this is a long walk of approximately 6km (3¾mls) and the last section from Pentire Farm back to the Car Park is a bit of a drag.
There is limited parking at Pentire Farm itself, from where there are also some shorter routes.
Giving detailed turn by turn instructions seems a bit redundant as basically you head for where the green bits meet the blue bits, and keep going until you get back to where you started from. If your feet are wet, and you covered the last few hundred metres rather too rapidly, then you've missed the path (quite literally).
As fine a piece of coastline as you are likely to find anywhere in the British Isles.