To help you out more here's what you need to do -
In the Nicotine Strength e-
juice box you need to put 48mg ( also you need to know if your nicotine is 100% PG, VG or 50/50 mix ). You'll need to back out those numbers and put in what you are using.
Since your target rate is 36mg of nicotine you'll need to fill in that box.
Amount to make you'll need to fill in that box ( how much of a bottle you want to make...5ml, 10ml, 15ml....)
In the flavor box #1 put 0 since you are not adding flavor.
In the target ratio fill in what ratio you want ( ex. 50PG/50VG, 40PG/60VG.....)
Then click Calculate.
Please be very very careful when working with nicotine....
Practice with the calculator by filling out each box ( field ) till you are sure on what you are doing.