HE3D-XI3 3D printer Repetier software config help! I am new to 3d printing and had bought my first 3d printer a couple of months ago. I have it all put together and the software uploaded to the Arduino. However, I need some help with configuration and calibration of the printer. I understand that there is a configuration file that can be changed and uploaded again the create those changes. I also have worked with Arduino before so I know the IDE. 

When I turn the printer on everything works, as far as I know. I did some tests to see if anything was wrong, but I couldn't find anything. However, when I hit home for all of the x, y and z axis to go to their starting marks, it tries to go past the rails and comes apart. From what I understand this is a configuration issue. 

I tried to contact HE3D about this, but received no answer, so you guys are my last hope. If you need any more information to help me, let me know and i'll try getting it to you asap. (I also have read the documentation on Repetier and the installation and configuration section but my brain for some reason is not clicking into gear.) 

Thanks for the help in advanced!!! Here are the specs:
https://www.3dprintersonlinestore.com/reprap-prusa-xi3
Based on some troubleshooting in the question comments, it appears that the issue here is the motors running the wrong way. This can be fixed EITHER by inverting the motor directions in firmware, OR by simply flipping the orientation of the motor plugs where they connect to the controller board. Flipping the plugs is an easy and quick way to reverse the phase of a stepper and thus reverse its direction of motion.