How do I ask a specific question about math?

I was watching one of the geometry videos on YouTube and realized that I have a question. I decided to sign up here to ask the question and am having a hard time figuring out where on this site to post that question. I will post it here and see if I get an answer.

The definition of a point includes it not having any dimension. However the definition of a line segment AB is all the points between point A and point B. That is impossible given the definition of a point. An infinite number of points cannot get from A to B because they have no dimension.