Use tweezers to peel the outer ring off of one of the adhesive strip pads.
Be sure to get both the double-sided adhesive and the brown backing paper.
If you're having trouble navigating the double-sided adhesive, check out this video.
Be very careful not to fold, bend, or stretch the adhesive tape, as this will make it too thick to seal the screen without a ridge between the screen and the case.
Excellent! Apple claimed it was not economical to repair a watch with inflated battery that had pushed out the screen. I think 18 euro for a new battery and adhesive tape, together with this manual is excellent value, a new lease of life and less waste. :-)