I almost always start by reading the manual. With the Cricut, I did the same. I don't know if Cricuts typically come with the blade installed - mine didn't. None of the instructions mentioned installing the blade. I reversed the steps for removing the blade to adjust blade depth.
The steps on how to set paper size are unclear. I tried a couple of variations but was unable to set the paper length to 6 x 11.
First Impressions: C
I used printer paper to test out some functionality. When you first use a cutting mat, it's very sticky. I misaligned the paper initially and had a hard time repositioning it.
Next rookie mistake: I left the blade depth at 1 thinking the printer paper was thin. The blade didn't even cut through the paper. 2 worked much better.
Any DIY tools that you thought would be easy to use and weren't?