Timing of script pages
As a rough estimate, one page of a script equates to one minute of screen time. It is impossible to say exactly how long a page will last on screen because it relies on too many factors. 

You shouldn't worry about trying to make each page go for exactly one minute. You'll find that some pages will go over a minute on screen and some will go under. So don't start a new page - that'd be incorrect script formatting and if you give an incorrectly formatted script to a producer you'll have no hope of getting it made. 

I've found the best way to learn how to write screenplays (other than professional lessons) is to read screenplays. Here are a few websites that you can find scripts on:

Drew's Script-O-Rama

Screenplays for You

Simply Scripts

Daily Script

I haven't used Final Draft to write scripts before. I use Celtx and it's an amazing program. It's free and it formats the script for you as you go. I highly recommend it.