Yeah knowing what to do helps. I was completely nervous, I thought it was going to be a super hard battle. But honestly, it did not take me long at all. Like Mases said in his video, once you got him, you got him. I found Demise fairly easy compared to the second battle with Ghiriham. For some reason, that one always got me. Killed me a few times when trying to go through the battles for the Hylian shield.