git commands

[Antwnina]

$git init
Reinitialized existing Git repository in /home/nina/.git/

what happens afterwards???
$git add .

git commit -m 'first'

^C
$git commit -m 'first'

*** Please tell me who you are.

Run

git config --global user.email "[email protected]"
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 'nina@nina.(none)')

how can i recognize in which URL should i go
$heroku create
Creating app... done, ⬢ pacific-sierra-89270
https://pacific-sierra-89270.herokuapp.com/ | https://git.heroku.com/pacific-sierra-89270.git