Please display your image(s) in your post so we can see it(them) without downloading it(them). See this Simple Image Guide
Any Arduino should suitable. An Uno is the best choice for a beginner because most programs and add-ons work with it.
These links may help
Stepper Motor Basics
Simple Stepper Code
also look up the AccelStepper library
Serial Input Basics - simple reliable ways to receive data from your PC.
...R