Boris Karloff -- All His Actor Credits in the Thriller Series are Missing from his Filmography

Boris Karloff hosted the TV series Thriller from 1960-1962. In addition to playing himself as Host in all episodes, he appeared in 5 episodes as an actor, sometimes with the leading role. Yet the TV show Thriller is not listed in his filmography at https://www.imdb.com/name/nm0000472/?ref_=fn_all_nme_1. To be sure, if you look up each individual Thriller episode, he is given double credit in the cast list as both "Self" and a character. But the 5 appearances as characters have not been added to the main filmography. There should be a Thriller entry in the main filmography with the usual link to "5 episodes" over on the right of the page. Once before I posted a question here about a person who was listed only as "self" in a short film but also had a character role, and someone here explained how to make the change in a case like that, and I did so, but I have forgotten how and can't remember the title of my question on this forum so that I can find the instructions again. Can someone remind us all how to create a new entry in the main filmography in cases where a person who is listed only as "Self" should also be listed in the credited cast?