I bought a new Timber Ridge insert from amfmenergy about a week ago and I was taking the bricks out to lighten the load to move it and I just noticed that the back of the stove has no collar on it, its just flat. I know most stoves have a collar so that you can run a few screws through to attach the liner. How do I go about installing this with no collar? I have read about boots, is that what i need? My liner is from chimney liner depot and obviously has the appliance connector coming with it and i assume just slides down into the hole on the back of the stove but there seems like there isnt a way to secure it. I Will get a picture if that helps.