I looked it up and its a Thetford now had you put that as well then I would not have had to look it up.
Most lip seal packs carry instructions. However got to www.thetford-europe.com and click service look for the model and downloads and your model (200) series.
Look through book clicking the right arrow until you see lip seal. Then hopefully you can see how its done unless they've missed something out leaving you guessing.
Bob, February 2014