It all depends on what sort of servo it is.
+ needs to go to whatever the servo can take. Since you hooked it to 5v, I am guessing it is a 5v servo.
- needs to go to ground if it is a standard servo, again it depends.
So you can get these from the analogue input pins if it is just one servo. But if you do, try to have it powered externally as USB will not like to power a servo...
If the yellow is the servo control that takes a PWM signal and 50% finds middle, and deviations from that turn it left and right, then it is simple. But when you have it hooked up with just power and no input, it should be completely swiveled one direction and if you move it, it moves back. If it doesn't do this, then it is wrong.
Once connected you have to determine what kind of pulse it needs. Probably a square wave from - to + at some frequency and duty cycle. Hook the + pin to the servo feedback pin via a pullup resistor like a 10K, or 2K or something. Again, depends on the servo. Then hook that node into the - side of the digital output. Send the inverse of the pulse you want, and it should work.