This is post is a rough draft and will hopefully be refined and placeholder information filled in.

There is a skirt plate (boot?) under the router that holds the dust collection parts including the hose connection and the skirting.

This plate is adjusted up and down depending on your job and your bit to get the best dust collection possible at the point of cutting. There is a nut that you need to loosen at the back of the plate on the left. Use X size allen key.

The brush skirting is attached to the boot/plate with thumbscrews.

Do not adjust the nut at the front of router above the boot/skirt plate. This should be set and is only used to secure the router head. If you leave it loose it is very dangerous. Only authorized folks on a maintenance team should be adjusting this.