I've heard that in order to get a full page you usually use times new roman and the font size is 12 but at the top of the page when you put the chapter number what size font is that normally?? For example, if you put chapter 1 at the top of the page what size would that be??
I'm sorry, I'm afraid you've heard falsely. I don't know if you're talking about manuscript form (what the author sends to the publisher) or finished book form (what the publisher ends up printing). If you're talking about a manuscript, then put the whole manuscript in a clear, easily-readable, mono-spaced font (some people recommend Courier--time was when you absolutely had to use Courier to be taken seriously, but thank goodness that seems to be passing). Chapter headings use the same font as everything else. If you're talking about finished book form, then there are several answers: 1) There's no reason an author would need to know this unless you wanted to self-publish, which is only a good idea in unusual circumstances; 2) It varies from publishing house to publishing house and book to book; and 3) Personally I think the body text looks nice set in 11pt Garamond with 12pt line spacing and drop caps; chapter headings can be the same, about two thirds of the way down the page, in bold.
a submission ms must be ALL in the same type font/size... courier new or times new roman 12 pt... nothing in the ms should be any larger...