Go to reseller form and order one of the AutoVM reseller balance.
After order, go to product management and check your secret key.
Download AutoVM reseller module from the LAB.
Upload downloaded file in your WHMCS main directory and extract it.
Go to WHMCS admin area, Setup -> Products/Service -> Servers and create new server.
In the first part, enter AutoVM reseller.
At the end of the page, change the type option to autovmreseller and enter your secret key on the username part and click on the save button.
go to Setup -> Products/Service -> Products and create new product.
On the product settings, go to the module settings tab, click on autovmreseller and enter 30 for the days section.
Then go to custom field tab and create two field like the example.
Enable Required Field, Show on Order Form, Show on Invoice options.