How to drive two steppers at a same time

Hello. I want to make robot with stepper motors, I have two of them. And I want to drive them at a same time. I tried to put in code first one stepper one step and then another stepper one step. But I have no power if I do like this. Is there another options to do it? Please help me.

Sorry for my bad English I'm from Estonia.

Can you explain what you mean by "no power" - are the motors failing to turn or is the power supply struggling?

It helps to post the actual code you have and explain what motors and motor shields/drivers you have and how they are connected - there are many possible issues.