How to move post from default type to new custom type?

I’ve added two new post types for my website for a show truck. I’m splitting the site into two main groups, one group for the original project and one for the new rebuild. All of the posts are in the default “Posts” section. Because I’m using the Porto theme, I have two different layouts depending on which group of posts is being viewed. Now I need to move the pages to one of the two new post types so they will use the corresponding layouts. I do not understand how to associate a post with a given post type.

Thanks