How to clean an octopus - and is it worth it
This a a great video that explains every step. She cuts the head off by slicing above the eyes, so removing the beak is a part of cleaning the tentacles.



These are your first cuts.

Cut the head off above the eyes, and slit the head open. Rinse out the guts, there will be some connective tissue that needs to be cut away or broken to get to all of the yucky stuff. Rinse thoroughly and peel. It's easy.

Cut the tentacles away below the eyes (the slice now that contains the eyes can just be tossed). That will expose the beak, which is at the center, where the tentacles meet. That just pops out.

The tentacles can just be rinsed and cut as desired.

Easy, and totally worth it. Good luck.

Of course you can keep the octopus "whole" by slicing out the eyes in a kind of pie wedge shape cut, exposing the beak and guts to be cleaned away but keeping the connection between the tentacles and head intact at the "back", otherwise following the instructions in the video.