Recommand "https://stackabuse.com/git-merge-branch-into-master" to lean about "Git: Merge Branch into Master"
It's very clear, I.e. steps:
git checkout master
git merge new-branch
Operation step in Intelli JDEA https://www.jetbrains.com/help/idea/apply-changes-from-one-branch-to-another.html#rebase-branch
Steps:
Right-Click checkout master
Right-Click another branch, Merge into Current
Managing the remotes and it would be powerful jumping between defferent remotes
https://www.cnblogs.com/backuper/p/Version_Control_System_Create_Git_Repository_push_to_multiple_remotes.html
then managing the branch merge action.