If the plugin is placed in the right folder, vvvv should detect it and give it pins in your patch.
Once that is settled and still nothing is connected you should check the help file coming with the background patch. Video in leftmost pin, then somewhere you can add a transform to adjust the image. With IOBox(enum) you can choose which method to use with the suppression. I would go for threshold. Add another variable box to adjust the threshold.
The output of the background suppression should go in the renderer you see. From the Asvideo node you connect it to the contour-node.
