rm-f. Git / index.lock delete the index.lock file before executing git add.

delete this file again
to learn to read the error log

should be merge before commit, you commit to try

the workspace has modified files, when Push, you need the workspace to maintain the clean state. Use git status to check the status of the current workspace, commit and push if you are sure you want to modify it, and vice versa, use checkout. Discard.