In order to form a set, go to it, either by clicking once in the left tree column, or by double-clicking in the central area of the screen.  

You will see another tree-like section with your catalog, from which you can select the equipment or services that will be included in the package.

Next to the elements there will be a plus icon, clicking on which will add the equipment/service to the kit. 

If there is a need to remove an item from the kit, then select it and click on the "Trash" icon, which will be located in the upper left corner. 

As the kit is formed, you will see the sum of prices and other parameters at the bottom of the screen.

You can add another kit to the kit. However, if the added bundle contains another bundle, the action will be canceled.