Typically once you have cloned the master branch, and that is the only branch you have, you can just do the equivalent of...
Start Git Gui
in the menu select...
remote/fetch from origin
and then in another part of the menu select
merge/local merge
That's it, your done and it is updated to the most current version.
In the simplest of terms what Git does when you pull from the master branch is to give you the most recent version of that branch by adding only the changed files VS everything all over again. Think of incremental backups and the way they work. When you do an incremental backup it only saves data that is new or changed. This works in reverse and adds to your aircraft directory only the files that are new or changed. You don't really have to know or care what files have changes so long as the repository manager tells you what branch to use to keep current. Typically it is the "master" branch. It is is all the repos I manage. I add all my new stuff to the master repo and I try to make sure that branch is always stable. Some do it differently and use versions and what not. But I gathered your looking for the latest development.