Before you start your own experiments, perhaps you should try this:

To view the orbits with the default values, click on Play and observe how the eight bodies chase one another along a circle. By changing the masses of the bodies, you can control the shapes of their orbits.
This is how you change the default values. Click on Pause and then on Reset. By way of an example, to change the mass of the red body, hold the mouse cursor over the first field that displays the value 3.2E29 in red. The label reads "Mass0". This is the mass of the red body in the scientific notation. Click into the field and change it to 3.2E30 (ten times more). The background color of the field changes to yellow while you are editing the number. Hit Enter when finished. The background color changes back to white to indicate that the edit is finished. Click on Play and observe drastically different orbits of all bodies. You can change any of the remaining default values of the masses by the same technique.

When making other experiments with the model, always remember to Pause and Reset before changing any defaults.