Step 2: Set up your characters
First let’s start with Mario. He will be sprite 1. upload either of the images I provided you or your own by first clicking sprite 1, then click costumes, then click edit, then import and then find the Mario image you are looking for. Once you have done so it will go back to the screen where you clicked the import button which is like Microsoft paint, but better. Your image is likely on a background colour of some sort, so go to the 'fill' tool and click the colour in the bottom right corner (the four small grey and white squared colours) and then click on the background. It will turn it into the surrounding colour. This allows you to completely focus on Mario.
I noticed that I couldn't find a walking Mario, so I decided to make my own out the jumping Mario. First you must copy the jumping Mario by clicking copy, then click edit, remove the background of Mario, and then copy his arm to the right and in front using the stamp tool. You are now going to work on that arm using NOT the paint brush, but the line tool in g+w colour. The reason for this is that with the paint brush you have to be very careful where you move it as it could destroy your whole piece and you'd have to press undo and start over, whereas the line tool only goes where you tell it to. Once you have done this, flip it horizontally, set it aside and get to work on his arm to the right that's behind him.
The major thing here is the thick black outline that joins to his head, hat, nose, moustache and body. What you need to do is use the line tool to make a g+w colour line where the black outline of his arm connects to body parts. Once you have separated his body outline from his arm outline, use the fill tool with the g+w colour on his arm outline, his hand and his arm. Once done you should get the image like the second image. Before you go on, change the fill colour to yellow and click the background. You should now see all the pieces that still need to be deleted using the eraser tool. I suggest using the second smallest size as the smallest size can get lost in the colour black.
Once you have finished editing Mario, use the select tool and move him over his arm. You don't want to see it coming out of his foot, so keep jiggling around Mario until you get him looking like image 3. Once you have done this click OK and save your piece. Remember to do this regularly. The last thing about Mario is that you need to make him look both ways, so copy each image you have of him, go into edit, select Mario and finally flip him horizontally.