Here is a demo. The editor is in the link below. Take a look and see if it helps you figure it out. If you have any questions about how it works, feel free to ask
The Bubble progress bar works off a percentage. So if someone is halfway through you need to calculate 50 somewhere (e.g. 50 / 100 * 100) and point the element progress field to that.
This often catches me out, as Excel percentages work on .5 being 50%.