Checkbox option on Gizmo theme

I used to have a checkbox multiple choice option on my site where customers can select 1 of 2 options as this is required information when ordering from us. Since changing to GIzmo theme it is stuck to default settings, i am unable to add a multiple checkbox or any other checkout options. Is this because of the blocks the theme uses?

I really need this for my business as some people miss their email asking whether they have an empty or deposit.