It's called Bouncing...
You need to bounce all of your files to a stereo file - it's also known as a mixdown (you mix down all of your tracks into a stereo track). You can make it dual mono, too, but I don't see why you would really want to.
Go to File in the top toolbar of ProTools and you should see a Bounce option somewhere in there. Give it a try - and do realize that it is performed in REAL TIME...meaning if you have a long track, you can go get some coffee and chill for a while.
"A lack of preparation on your part does not constitute an emergency on my part."