How do you get the dexcom platinum sites to stay on?

I just started on the dexcom today and the sensor started coming off after a few minutes so they put a dressing over it and now tonight that dressing is lifting off. How do you get the sensors to stay on? I was told I could take a shower or a bath but now Im scared to that its going to come off and they are too expensive. Please help..

There are several good discussions on this in the Dexcom group.