First you need to subscribe for plan according the credits you need.
You need to find your own customers. Here are some tips:
You can create a website
Send post on online forums
Create a social media channel like Instagram
Email Marketing
You also can find customers locally.
You can price service for your customers as you want.
Whenever you sold a subscription to your customer, open reseller panel, create a line and send it to your customer.
You can ask for more credits whenever you need.
