New Crew Member

To add somebody to the crew search for the person's name and select him/her from the drop down list. If you can't find the person in the list you can create him/her by selecting the last entry. Next, search for the person's job and select it from the drop down list. Finish by clicking Ok.
You can also assign a crew member to a season and inherit him/her to all episodes. This way you don't have to add the crew member to each episode. To do so, change to Yellowstone One Fifty (2022) and edit the crew there.