You should be able to insert

You should be able to insert a custom variable anywhere through selecting a variable from the "x" menu by selecting the "x" menu item. You can then edit this variable by tapping on it and tapping the edit button on the right of the popup that appears. The label, subset, and description for a variable can be entered here.

There is a slight glitch in the current version where a new variable with a blank subscript label will not interact properly with other variables of the same name (if you enter a number in for it, the other variables that match it won't change to reflect this new value). This can be worked around by entering something in the subscript, tapping to another field, and then clearing out the subscript field. I'm working on a fix for this for the next update.

Sunset Lake Software - Comments for "Basic question.."

You should be able to insert