3: you cannot use the background layer freely, you would have to pay to use it.
The folder in the top right of your screen, is for seeing what animes youve made, click one and you can edit them. Long hold and you can delete it. The house is home, the smol human is your page, the bell is your notifications.
4: the three dots is other stuff that I don't know about. =>=
And lastly 5: Free draw anytime, the more you spend time here the more famous you'll be and youll become a great artist!! Enjoy ^^