I don't know like to create a new repository.
I need to finish a project but I don't understand anything about the repository creation step.
If you have a pre-existing codebase on your machine (which I assume is the case), and you need to "upload" this codebase to GitHub, then you would need to perform a few actions:
Create a new repo on GitHub. If you are not familiar with the command line, I suggest doing it on the Web UI. You should follow the link in @Ben's answer: Create a repo on GitHub
Initialize a local repo on your machine. To do this, you should fire up a terminal and cd into the folder of your codebase.
cd /path/to/your/code
git init
Link up your local repo with the remote repo on GitHub. Go to your newly created repo, copy the link as shown in the picture below:
Ensure you are copying the https URL. The ssh type URL requires a little bit more configurations, and you can do this when you are more comfortable with working with git and ssh tooling.
Then run the following command:
git remote add origin <your repo url>
You can read more about git repo, remote repo and local repo here
Commit and push your code.
git commit -a -m "initial commit"
git push origin main
# you will be required to enter your username and password
GitHub requires you to use a Personal Access Token if you are pushing your code in the command line. You can refer to this link to create a PAT for yourself.
The next step for you should be learning more about the git tooling. I would recommend reading Atlassian's git tutorial, or the Git book
If you new repository is one you want to create locally and on Github, you can do so easily with the GitHub CLI gh.
Once installed, authenticate yourself with gh auth login, then create your new repository with gh repo create.
If you don't have a repository yet.
# create a new remote repository and clone it locally
gh repo create my-project --public --clone
If you already have a repository locally.
# create a remote repository from the current directory
cd /path/to/my/local/repository
gh repo create my-project --private --source=. --remote=upstream
git push -u main
Use --public or --private depending on the visibility you want to associate to the new GitHub repository.