HEAD refers to your local repo. So, between "<<<<<HEAD" and "====" is your changes whereas below "====" are changes that your teammates made.
for example, if you are working on App.java and made some changes in your working directory and "git add" the changes, the changes that you made is staged and goes to the staging area. furthermore, if you commit after, with all the changes, it creates a new node (new version) in your local repo.