I've found a better relay option for you. The reason I went looking is because the relay link you provided capped its load at 10A.

http://www.amazon.com/Sunkee-Solid-SSR-25-3-32VDC-SSR-25DD/dp/B00CI4HBCQ/ref=sr_1_1?s=electronics&ie=UTF8&qid=1432473010&sr=1-1&keywords=DC-DC+SSR+3-32V

Most heated beds require around or above 10A, so this 25A relay can load 10A no problem. Same specs for the control voltages.

For wiring, i've found a simple wiring diagram on google. http://i.imgur.com/mZg7k6D.jpg