A box set allows you to link multiple albums together. You can create a new box set from either the Box Set View, the Album View, or the 'Album Edit' window.
Edit box set in the 'Album Edit' window
To create a new box set from the 'Album Edit' window, click the Add Box Set button below the Box Set field. This will open the 'Box Set Edit' window.
To link the album to an existing box set, simply select the box set from the Box Set field drop-down list.
To go to one of the other albums in the box set, click the Album button and select from the menu.
Create a box set in the Album View
Select all albums in the box set in the Album View list, then right-click and choose Create Box Set from the popup menu.
Manage box sets in the Box Set View
From the Box Set View you can manage all box sets. Here you can also add new albums to a box set, remove albums, or rearrange the album order.