I have a little problem. For you, that problem maybe entry and very silly, but that it is....

I'm new user of ARENA Motion Capture Software. Well, until now I have never used similar software.
I downloaded your video tutorials, but they didn't help me.
My problem is that I don't know how to calibrate cameras. I assume that prior to any motion capture is calibrating cameras. I tried wanding, but on the monitor I didn't have any curve like you have on your video tutorial.
If anyone knows where I made a mistake, please, tell me. I have a very little time to learn how to use this software and I don't have anyone to help me. This forum is my last hope.
Can somebody tell me what to do step by step?
I have 6 cameras and they are mounted and connected as you suggested.
Best regards