How to just control stepper motor and hotend temperature of 3D printer extruder?

I am a total beginner of Arduino and 3D printer. Is there anyone would like to share the code or source to control these:

1, I've got a hotend kit which already has the thermocouple and heater. How to control the temperature?
2, Nema 17 bipolar stepper motor and Easydriver. How to get a reasonable speed to make it available to push the filament through the nozzle smoothly.
Thank you so much!

For heaters you would typically use a PID control loop and a PWM output to modulate power to the heater through a MOSFET. You will need hardware to read the temperature sensor. Often they use a thermistor rather than a thermocouple. For a thermocouple you need a specialized amplifier chip. For a thermistor you need an analog input and the right formulas (See: Steinhart-Hart Equation.

For a stepper motor you need a stepper motor driver and software like the Stepper library or AccelStepper library.

For the stepper motor stuff these links may help
Stepper Motor Basics
Simple Stepper Code
AccelStepper library

...R

Thank you Johnwasser,

I just messed up the thermocouple and thermistor. That's a really good point! Since my hotend comes with an NTC 3950 Thermistor, I think I have to use PID control. Do you have any source to recommend? Thank you so much!

There is a PID library. Go into Library Manger (Sketch->Include Library->Manage Libraries...) and filter for "PID". I think "PID by Brett Beauregard" is the one you want.