Start with

  $ git clone ssh://git@gitlab.cern.ch:7999/usatlas-hllhc-muon-mdt-trigger/L0MDT_IntNote.git

Then create a branch to work in

  $ git branch EH_draft    // once, to create branch
  $ git checkout EH_draft  // witch to working in this branch
  $ git status
  $ git add <file>  // Add all the files that you added or CHANGED
  $ git commit -m "comment" // update files tagged with add to local repo
  $ git push origin EH_draft