Just starting out - some help with exposure?

Hey. I've been researhing screenprinting for a while and now i have decided to start up. Hope this site works well. So far so good. Hoping people could lend some advice on starting up and, should i buy new or used equipment and,what are necessary tools and methods. Oh yeah, and what emulsion should I use. I got a small kit and I believe I may be using either not enuough emulsion or im not exposing long enough or too long. Its a diazo 2pt mix, but its so thin it barely covers the screen. Ive watched a bunch of videos and the emulsion looks way thicker and either pink or yellow. The stuff i have is thin and aqua. Im using a 500 watt halogen with the glass removed to expose for 12 min at 18 inches.