Somatrasiel

Hi guys, Upgraded to the professional version a few hours ago and I'm trying to sketch on the Paint Tab. However, I'm unable to actually paint- as my cursor won't change into the brush and I keep getting "Please Choose an Option" down at the bottom. I'm basically just trying to do this. I'm not totally new to 3dcoat, but I'm having trouble figuring out why I can't paint! Any help would be greatly appreciated, thanks!