I've seen where you can use a flower nail to bake a level cake but I'm really not sure HOW to do this? I don't have a "core" for baking larger cakes and I need to bake a 12" round.

Here is a link to a tutorial on CC. Hope it helps.
http://cakecentral.com/articles/651/cake-baking-flower-nail-method-tutorial

Thankyou! I'm still having a little trouble navigating and searching for topics so sorry to anyone who has seen this question before

You're welcome =) I understand that.

I have used the flower nail as a heating core but hated it. I don't think it did anything. I bake at 325 degrees and my cakes are level every time. I have used the heating strips (Wilton, bought at Michael's) and they seemed to work fine. I quit using them though when I started lowering the temp from 350 to 325 because the cakes were level without them.