NEMA 17 ONLY CLUTTERS

hELLO everybody It is my first post.

Recently I bought a Prusa i3 kit from a local supplier. I get no customer service as expected.

Here is My problem.

I fnished the assembly and barely understand firmware setup and installed it to arduino. Now I am trying to make steppers motors work. I am sure they are correctly connected to ramps but. When I try to move them with repetier manual G codes. They move a bit with alot of noise and then become clodded with a fixed noise.

Questions:

If problem is from voltage where can I adjust the voltage.
Which values in the firware could cause this problem.
If somehow I break the steppers or stepper driver how can I verif it.

Here is the stepper model

17HS3001-20B 40.0 N·cm 2.0 V

I run with Arduino 2560 and RAMP 1.4

Many thanks for help