Homing problems with z axis

I run the homing and the z axis goes down instead of up. This is a brand new machine and can not figure out what’s wrong. Someone else tell me what to do?

Probably you have installed the Z-axis spindle carriage plate upside down (the static pulley should be on the left when viewed from the front of the machine). Flip it over

There’s an article on machine orientation / movement which lists some other options just in case.