The joystick is read as direction and control in their simplest form: left, right, forward. Dream books link it to how firmly you feel you are holding the course of things.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.