I just received a pad of Stonehenge aqua hotpress and am delighted! But how do I get the pages apart without damage?

To remove the top sheet there is a “notch” found on the top of the block when opened. This notch is a small spot which is not glued and where you can slide a pallet knife (or any hard and flat object) in to slide all the way around and separate the top sheet exposing the next sheet to work on.

Here is a great step by step video for reference:
https://www.youtube.com/watch?v=LTCVGdYLlNk&feature=youtu.be