Firstly, congratulations. You made it. It is not an easy thing to get your PMP certification. Despite the fact that there are more than half a million PMP certified professionals, it is no ordinary feat to become one. Now that you have done that, make sure you take care to keep the credential active.
Once you have attained your PMP Credential, you must participate in the Continuing Certification Requirements (CCR) program to maintain an active certification status. The PMP credential has a validity of three years, after which you have to go for a renewal of the certificate. This three-year period is also referred to as CCR cycle.
The CCR program encourages ongoing educational and professional development of PMP credential holders.
As a PMP credential holder, you need to earn 60 PDUs (Professional Development Unit) per three-year cycle after obtaining PMP credential. One PDU is equal to one hour of time spent in a Professional Development activity. You can gain PDUs in multiple ways.
PMI has documented the details of these here
You may also want to go through these videos from PMI for more information on how you can maintain your PMP credential.