@agapanthusblue I have to admit I am not sure I understand your question, so please accept this input as I have learned how to commit changes to gitlab with tags.
Say you have a working directory of /home/agapanth/your_work and all of your code resides here, along with your .git subdir residing in this path precisely.
And your code is at version 1.3.0, and you wish to tag it as “Rev-1.3.0” specifically (for this example).
You would do the following:
Change into working directory:
Add working directory contents into staging directory contents:
git add -A .
Tag the based on the term “Rev-1.3.0” with a human-interesting-message:
git tag -a Rev-1.3.0 -m "Commiting changes that make this Rev-1.3.0"
Confirm your tag was “received” in the staging copy:
Send your change up to the Gitlab Repository (already defined in “origin”):
git push -i origin Rev-1.3.0
Pardon my ignorance if this has nothing to do with what you are trying to accomplish.