How to apply ALB Custom Layout to all Portfolio Items?

I’ve watched the video on how to add a custom template to a new custom post type (in this case Portfolio Item). However, I would like to set up my child theme so that each Portfolio Item, when created, will already have this custom layout set up. I’ve looked throughout the settings and I cannot find a place to set my custom layout for ALL instances of a custom post type. Can you help me? Thank you in advance for any assistance.