In order to login to cPanel, you will need to either know the hostname of your server or your DNS propagation should be complete.
Option 1: Server Hostname
This is the best option to use before your domain has propagated. Your server hostname will be in your welcome email, alongside your username and password. To login to cPanel, go to https://(your server hostname):2083 and enter the username and password provided to you in your welcome email.
Option 2: Your Website
Once your DNS records are pointing to your hosting server, you can login by going to yourdomain.com/cpanel and following the instructions.
Next Step: Change your cPanel Password
