chore(tuto): add content

Author: bene2k1

tutorials/overleaf/index.mdx

@@ -216,11 +216,10 @@ sudo certbot --nginx certonly
     service nginx restart
     ```
 
-## Verify your installation
+## Creating a first admin user
 
-1. Access Overleaf via your browser at:
-   ```
-   https://<YOUR-OVERLEAF-DOMAIN>/launchpad/
-   ```
-2. Follow the on-screen instructions to configure admin credentials.
+1. Open your browser and navigate to `<http://<YOUR_OVERLEAF_DOMAIN>/launchpad/`. A form displays, prompting you to set up your admin account by entering an email and password. After filling in the credentials, click **Register**.
+
+2. Follow the link to the login page (`<http://<YOUR_OVERLEAF_DOMAIN>/login>/`) and enter the credentials you just created. Upon successful login, you'll be directed to a welcome page.
 
+To begin using Overleaf, click the green button at the bottom of the welcome page. For more information, how to use Overleaf, refer to the [official documentation](https://www.overleaf.com/learn).