You need to install the plugin Webnus Portfolio via this article and activate it. Install Plugins Then a new menu will be added to WordPress dashboard panel called Portfolio.
In Portfolio submenu: Portfolio shows all the posts.
In Portfolio submenu: Add Portfolio Item, you can add a new post.
In Portfolio submenu: Portfolio Category, you can set categories.
In Portfolio Options, you can set which style to be shown for the next and previous posts navigation. You can also show the Related Works, you need to check its checkbox.