How could you fold for the circle cp ?

[Nobita]

Thank you vey much for you kind help. I can compleat the frog already
this my really first step for folding by cp. I really thanks for your instruction. However I see the small circie in the big circle in you cp posted above. what does it really mean . I don't use the the line inside that circle in my folding. Explain to me please.

[Jonnycakes]

That is a point split. I believe there is an article on Fishgoth's site about the subject-there is also a thorough explanation in Origami Design Secrets by Lang. You will need to sink the point thinner before you split it.