First of all you need the Multi Portfolio plugin installed. You can install this plugin as explained here:

Getting Started with Black Label 4 > Recommended Plugins

Once you have that plugin installed, a new menu is created called Portfolio, go there and click on Add New item:

Add you Title and Content as normal and select your Featured Image here:


Also you will see a section called Portfolio Item Options, with these options

Select layout

Here you can choose if you want a normal size item or a big one. Example:

Portfolio Images

Here you can add all the images to display on the single page of this item. Example:

Single Portfolio page

Two options here, Default or VerticalThis is how you will see the single portfolio page.

Example Default:

Example Vertical:

Portfolio Categories

All the portfolio categories you select here will be used for the portfolio filter: