I am new at working with Arduino and I know only the basic about electricity, this is my first project. I am using Arduino Uno with two step motors Nema 17, one works then stops and the other one works and repeat the cycle , with two drivers L298N one for each motor and the power supply is a 12V 10 Amp adaptor, everything works but the power wires get extremely hot, can somebody tell me how to solve this and what the problem is?
The ancient L298N is NOT a stepper driver. It is a brushed DC motor driver for small motors, and because it uses outdated technology, works poorly for that.
Ignore any tutorials that suggest you can use it as a stepper driver.
Buy a stepper driver that can easily handle the rated current for your motors. Pololu has a good selection.
Thanks jremington, I just followed the tutorials I found and several of them were using the L298N.
Most probably you already killed your poor L298N drivers and consequently the wires get hot from those chips or motor coils. How thick are the hot wires?
There are lots of really bad tutorials on the web, mostly posted by people who have no idea what they are doing, but managed to get something to work for just long enough to create a misleading web page.
You should trust very few of the technical tutorials that you find in the wild, especially Instructables, who have no quality control whatsoever.
Vendors like Sparkfun, Adafruit and Pololu post tutorials that can usually be trusted.
You need heavier gauge wire (a lower gauge number). Wire Gauge Chart
Normally we just assume wire has zero resistance but it does have some resistance depending on gauge and length. A fatter or shorter wire has less resistance.
When current flows through a resistance we get a voltage drop (Ohm's Law) and voltage & current together make power (energy & heat). If we can reduce the wire resistance, we reduce the voltage drop and the heat.
A shorter wire will also reduce the resistance but the remaining heat is more concentrated so it doesn't help with the wire heating. (It does help with voltage drop/loss which can also be a problem.)
You need to post full details of the hardware you mention, that means links to the datasheets or product pages, so we can know precisely what you have. Details like this are usually vital.
So motors, motor shield and power supply details please. You probably will need to replace the L298N shield with a stepper driver suited to your particular motors.