You can find most of this on the internet but for the sake of complecity of this session below are the commands that I personally find very useful
git status
# To add 1 file
git add 'file-name'
# To add all untracked files
git add .
# To add all files inside a directory
git add 'directory-name'
git rm --cached file3.txt
# to commit
git commit -m "message"
# to uncommit & and get your changes in unstagged area
git reset <commit-id or ref> ( commit id or ref of the changes after which your new commit changes came)
# git reset works with file name as well, if you want to move a file from staged area to unstaged area
git reset <file-name>
or
git restore --staged <file-name>
# to trash your commmit changes
git revert <commit-id or ref> ( commit id of the changes you want to trash)
# to trash your commit changes of a single file
git restore --source <commit-id where original changes were present> <file-name>
git show <commit-id>
git checkout <file-name>
or
git restore <file-name>
git cherry-pick <commit-id of the branch from where your want to pull changes>