Welcome to AA btw!
There are a lot of options in building your rockwork. Acrylic rods, PVC
pipe, just about anything that is non metal and wont leach anything into the system can be used to construct your reef.
You can bore holes in the rock and stack them onto PVC
pipe and fasten them with zip-ties. The sky is the limit. The best thing to do is get your rock first and see what you have to work with and go from there. I'll look through my links and see if I can find the page where a guy does a step by step build of his rock. Great images and a lot of good tips.