how do you set up 12 motors?

How do you use 12 motors if the maximum number of motor ports in a cortex is only 10?

Y cables

You could use Y-splitters.

Some info:
https://vexforum.com/t/vex-and-lab-view/14601/1
http://www.vexrobotics.com/media/catalog/product/cache/11/image/5e06319eda06f020e43594a9c230972d/f/i/file_30_1.jpeg

or even better use a power expander so you wont lose current.

Whats a power expander and would i need one if i had 12 motors

You don’t lose current using only the cortex.

Just lets you attach a second battery. Running 12 motors can drain the battery faster and some people want to have a second battery.

would u reckomend getting one if im running 12 motors?

A lot of teams have done fine running 12 motors without it.

@tabor473 ok thanks that answers what i want to know

You could use Y-splitters. This will allow you to have 12 motors instead of 10. However, if you do this, I think that both motors on the splitter need to be going the same speed and the same direction.

Unless you invert it through wiring

If you do make sure to reverse it after the motor controller. If it is reversed at the y cable, neither motor on the y cable will run.