First of all, open the cpanel page and login with the details provided to you. Then after logging in you will get a page like
This is the window which will be shown to you.
Now if you want to create a new database or modify the database then just go to the database section and click on MYSQL databases.
Now fill the database name and click on create database then you will see this window where you can see that database is created and then click go back.
When you will click go back home page of database will come and there you will see that your database is created.
Now when the database is created you can add new user also by just filling the details. And after filling the details click on create user and the user will be created. And you will be redirected to the page like.
Once the user is created you can set privileges for that user.
After setting the privileges click on make changes and then click on go back.