All you need to do is measure your machine. Make sure you get the width, height, and girth. When doing the width measurements make sure to add the wheel in that calculation.
Once you have them all measured you need to cut them out. Be sure to add a good inch to inch and a half extra to allow for seems.
You will need 4 pieces. once you have the front pieces cut and sewn, add the sides. Carefully pin the sides on. I found that my curve didn't go the best at first. So go slow and be sure to tug the curved portion tight. I would not cut off the access until you have the curve just the way you wanted. All in all a very simple project.
You could easily add some pockets, ribbon, ect....