How do you wire the DC/DC converter?

[random_hero]

We are working with our extra robot for something to do in our down time. We have blown 2 D-Link bridges when powering on our robot.

We are going from the 12V port on the power distribution blue thing, to the dc/dc converter, then from the dc/dc converter to the bridge. As the negative cable on the d-link cable that we cut, we are using the wire with the dashes on it, which i assume was the negative cable. What are we doing wrong? Thanks.