Where is the Image Gallery of Portfolio Items?

Hello: I have installed this plugin and when i add new portfolio item, there is no image gallery.
I only have a featured image but i need the image gallery box in order to add images for the proyect and to be able to show them in the portfolio item page
Is there any option to add the image gallery box to the edit portfolio item page?

The page I need help with: [log in to see the link]