If you make changes on your local repository you can add all your changes to your local history with
git add .
With the . you add all new files to the local history. With this command you commit everything to your local git repository.
git commit -m "new changes"
You can do multiple commit. If you feel you are done and everything is good enough to share it with your co-workers you can push all your commits to the server.
If you want the updates from your co-workers you have to pull the changes.
Git pull is similar to svn update.