Today I started folding the Yellow Bird by Satoshi Kamiya. It has been really easy so far but now I'm stuck on step 23. (Out of 80...

In step 23 you have to do a petal fold and, although I know roughly how to do this fold, I'm not quite sure what the diagram is telling me to do.
Up until now, when making any folds, reference points that were created during pre-creasing showed me what point in the paper I was to fold to.
I don't think the bottom edge of the shape will go all the way to the top of the triangle when you petal fold it, but how do you determine where to aim for?
Hopefully some of that can be understood, sorry I can't explain myself a bit better.
Thanks
