it usually comes in 2 stages, 1st create a new WebApplication up to having an actual site running, and thats whats this post is about.
2dn part here.
1. Open Central Admin
2. Go to "Manage Web Applications"
3. Click in the ribbon on "New" to create a new WebApplication
and when you scroll down also
and after a long wait...
5. Click "Create Site Collection:
so that you get this window, and fill the relevant inputs
6. while this is going, you'll need to teach your local DNS the address for you new site, so open the "Run" window by pressing the window key + R and input "drivers"
7. open the "etc" folder
8. edit the "hosts" file. note that in some versions of Window you must either open "notepad" as administrator or copy the file outside this directory, edit it, and copy it back.
9. Add the new domain as 127.0.0.1 if you are going browse it in the local machine, or get the right IP for another machine.
10. back to the central admin, there will be a "created" screen, with the new domain url
11. Click it and get to work :)