You can set multi-levels on your script so every affiliate can invite other users to register under his level and the top level that sent the invitation will always earn a commission for every activity that is done under his tree level.
For example, if we have Affiliate-A and he sends an invitation URL to his friends or shares it anywhere, and a new user registers to be your affiliate from the Affiliate-A invitation link.
So now, Affiliate-B will be under Affiliate-A.
All activity that will have on the Affiliate-B account will affect the Affiliate-A account and he will get an auto commission from every activity Affiliate-B will do on his account.
That commission is set by admin under the left menu: MLM>>MLM Levels
Admin will be able to set the number of mlm levels he will have on his site, Script supports a maximum of 20 levels.
Admin is able to set the value of Sale, Action, and Click of every level that is active.
These two links will help you understand how mlm is working:
1. Case 1: MLM for local store module: Read Here
2. Case 2: MLM for your own store/site external sale integration: Read Here