On my phone, it's if you go to the frames button when you can scroll to see them all, on the right top corner there's a button to change the size of the canvasand turn the anti alias thing on.
On another note I'm genuinely so exited to start drawing your challenge I was getting ready to fall asleep last night trying to find a word or a feeling that would fit me and that I'd love to plan drawing and it hit me so I started planning out the environment and the lighting and everything raaahh I wish I could travel in time to the the result