Hi, brat.

Adding a person always needs to be done via a specific movie's, show's, documentary's, etc.'s TMDb page (its Cast or Crew list's editing screen).

For something that the person appears in or is on the crew of, click, on its Overview page, on Edit, to take you to that title's editing options. Then select Cast or Crew (whichever is relevant), then click on + Add a New Cast Member, add the person's name, then the name of the character they play, or select a crew position, then click on Save.

Incidentally, if you're adding someone via a t.v. series, the person should be added via a specific episode, unless the person is a series regular.

Doing those steps adds the person to the TMDb database. If the person is also in the IMDb database, you should add their IMDb # to their new TMDb profile.

Thanks gen.