Hi
First of all, the extension doesn't have a form module at the moment. However, I believe you can try the solution below :
1. Make sure you published the Payment Form content plugin .
2. Create an article, load the form inside that article using the following syntax :
{jdform FORM_ID}, please remember to replace FORM_ID with ID of the actual form.
3. Find a way to load that article inside a module (I believe Joomla has many modules, plugins allow you to do that.
That solution should work !
Regards,
Tuan