Good Evening,
What you have received is your Green Card. As others have said get your unrestricted SSN card. This is the end of the road for 2 years. As you go keep documents that you will need for your Removal of Conditions (ROC/I-751) in 2 years. To view the documents you will need go to guides and look for the I-751 guide. About a year after that you can also apply for citizenship.
So....you are done for now. Sit back and celebrate!! Congratulations!!