Credits on TV shows must be added directly to the episodes that you worked on. To submit your episode credit, start at the main title page for the television show. (For example, see the television show "Playbook" here.) Look to see if the episodes that you worked on are already in the database by looking at the episode list - select it from the left hand menu. (See episode list for "Playbook" here.)
If the episodes you worked on are already present in the database, go to the specific episode and click the update button at the bottom of the episode's title screen. From there, select "add cast" (or whatever credit you're adding) and submit your credit.
If the episode(s) you worked on are NOT present in the database, you will need to add them as new episodes first. Go back to the main title page for the television show, and select "add new episode"
You'll be prompted to enter in the basic information about the episode (title, airdate, episode number, etc), and after you've added that information, you'll be given the opportunity to enter in other credits (such as cast, director, writer, plot summary, etc). You can and should add your credit on the episode at the same time.
For more information on how to add new episodes, please see our guide here.