You mean deviantART muro? I actually use it all the time. You may want to switch to Pro mode if you want to use layers and more options. It's far better.
Oh, and saving it to the computer is easy. Well, you go to File > Export image, then you get a popup with your drawing in it, which you right-click and save. Easy.
The actual drawing? It's okay for a beginner. I were not that much better myself, when I started. I just made random sketchy doodles back then.
And just to let you know, you can upload all sorts of image files to your deviantArt page. Not just stuff made in muro.