Help with setting up servos?

Hey everyone, I've been researching on how to get stuff motorized, especially for Iron Man's faceplate, and it seems everyone uses servos. I then started researching about servos, but I'm still really confused so can anyone give me advice?

I believe you need the servo and a servo controller correct? But then people start talking about resistors, capacitors, transistors, etc and we also have to connect it to a computer to create a code to move the servo.

Is there a way to simply connect the servo to some battery and along with a button to make it move to a certain degree and then back?

Let me google that for you

Your local hobby shop sure sells them, the cheapest variant should work very well for a helmet project. Or you could buy a cheap RC model and salvage parts from there while studying the underlying technological principles.