[Gambas-devel] Cloned and edited. How do I get the changes staged, committed, and then uploaded to GitLab?

[First L. <d4t...@gm...>]

Guy, grew a pair and did the following: Got my account (zxMarce) at GitLab.
Created and added the necessary SSH Keys.

Then, cloned with "git clone https://gitlab.com/gambas/gambas.git
gambasdevel".
Navigated to "gb.db.odbc/src" and changed the old "main.c" with my changed
file from ye olde SF SVN tree (kept changes by bgermann from 3 days ago).

Then, I guessed I had to commit my changes to my local repo, so I tried
"git commit". But Git surprised me by asking my for name and email (wow!
heavier than the NSA!). I supplied my GitLab username and email, then tried
to commit again, but could not due to changes not staged (?!). The exchange
was thus:

   ~/gambasdevel$ git commit

   *** Please tell me who you are.

   Run

     git config --global user.email "yo...@ex..."
     git config --global user.name "Your Name"

   to set your account's default identity.
   Omit --global to set the identity only in this repository.

   fatal: unable to auto-detect email address (got 'xx...@yy...')
   ~/gambasdevel$ git config --global user.email "d4t...@gm..."
   ~/gambasdevel$ git config --global user.name "zxMarce"
   ~/gambasdevel$ git commit
   On branch master
   Your branch is up-to-date with 'origin/master'.
   Changes not staged for commit:
       modified:   gb.db.odbc/src/main.c

   Untracked files:
       gb.db.odbc/src/ml_doit.sh

   no changes added to commit

The untracked .sh is a script I made myself to quickly compile and install
the ODBC component. It should remain so.
But I don't know how to "stage" and then "commit" my changed file.
Then, I will have to deal with change-logging and uploading, but I'd like
to go "baby steps".

TIA,
zxMarce.