sea not see. Used to in this sense is implying that the fisherman went to the cliff all the time but now, he does not. Therefore, he used to go is a past tense form. So, you got it!

It means exactly what you think: the fisherman had the habit of going to the cliff every day, but he doesn't go there anymore now. (He's probably not even alive now, since the story takes place "once upon a time" -- probably a very long time ago.) It's more common to use the word "would" in a sentence like this ("Every day, the fisherman would go to the cliff...") "Used to" is a little more informal. It sounds like this is a story or fairytale, though, so the writer probably intends for it to sound more like casual, everyday speech.