Tracking Registration and 3rd party affiliate conversion

How can i will do this. I want to track 2 step (CPA/CPL and CPS) like:

Step1: People come from traffic source will go to my landing page > then complete a registration form > then go to thank you page > conversion fired & this conversion will be known as lead.

Step 2: From thank you page > they will go to a 3rd party affiliate offers from a affiliate network. > conversion from affiliate network will be known as CPS