STEP 1 : Login to Direct Admin ( Guide here ). Make sure your access level is on Reseller ( Top Right )
STEP 2 : Navigate to Account Manager -> Add New User. Click on Add New User
STEP 3 : You will see a row of details like below. Fill up the details accordingly.
Username/Email/Password : Username/Password for the user
Domain : Primary domain for the user
User Package : Select Package for user. If you have not made one, use this guide ( Link Here )
IP Address : Leave as default, or if you purchased a dedicated IP, you can assign it here
Click on submit and the account will be created