Once a new line is added to your equipment list, you can click your mouse on the description column or typing in the description column brings up the equipment selector (known as the 'popstock' window).
Once the popstock window appears, one or more pieces of equipment can be selected by either clicking on the description of the equipment, which will increase the quantity requested by 1, or by typing your requested number in the" Q" column. To decrease the quantity, right click your mouse until you reach the desired number.
Pressing the 'enter' key or clicking on the button will add the selected equipment to your list.
button will add the selected equipment to your list.