In order to customise your tuning for your instrument use the editor to define tones for each string of your instrument. To bring up the tuning editor press the edit button on the right of the chromatic tuner.
Change any tone in the selected tuning by selecting the string and scroll the note-drum to the left to lower the tone, or to the right, to raise the tone. Repeat the process with any other string you want to change.
Give the modified tuning a new name by touching the name field and typing in the name you want to give it. Finally, press the save button to finish editing, or press cancel if you regret any of your modifications.