https://git-scm.com/docs/gittutorial http://learngitbranching.js.org/

INIT NEW GIT PROJECT
CLONE EXISTING GIT PROJECT
MAKING CHANGES
MANAGING BRANCHES
MERGING BRANCHES AND MERGE CONFLICTS
CHECKOUT REMOTE BRANCH THAT DOES NOT EXIST IN LOCAL REPO
CHECKOUT A PULL-REQUEST FROM GITHUB
UPDATING LOCAL REPO FROM REMOTE REPO