Saleem,
In order to earn your PDUs you have to
1) Watch at least 35 hours of the lessons.
2) Take the final exam to show that you have learned what we were teaching (PMI requiremement)
3) Receive/print your certificate (automatically displayed on screen after you pass the final exam in the previous step)
4) Claim your PDUs from PMI on the CCRS website.
There is no time limit. You can take the Final Exam whenever you like, but you must follow the above steps (all of them) before claiming.