Click the letters to change the letters in the variable. I don't know how to create a backspace key, so there's a red x that will erase the entire variable. When you press enter, the variable will clear, but it will be saved in a list. Press "Hide OSC" to see it.
Yes, I know the abbreviation for "on-screen keyboard" is spelled incorrectly, but it could've been worse. I got up at about 6:45 the morning this was developed (which is very early for me) so my brain is kinda messed up.