In the plugin configuration create any alpha-numeric Secret Key.
Create separate products in aMember CP -> Manage Products for each corresponding product from DealGuardian.Com
In your DealGuardian.com account -> Vendors -> Third Party Integrations -> MEMBERSHIP SITE SCRIPTS create integration for each product
which should be linked to aMember product.
Set Secret Key to the same value as you set in Plugin configuration.
Set URL to integration to https://example.com/amember/payment/deal-guardian/ipn
For each aMember product set "DealGuardian Product ID". You can get these values from
your DealGuardian.com account -> Vendors Third Party Integrations screen.