I tried it out two ways at home. I made a bunch of "droplets" on a craft mat and let them sit to dry overnight. They came right off the mat in the morning and I just applied a tiny drop of glue to put them on this card. I also applied them straight to a card - it's still drying. It is a water based glue, so they definitely stick to the card. I will post a picture once it's dry. The droplets dry clear and really do look like water droplets. One thing I have learned is to hold the pen at a 90 degree angle to the surface when making the droplet. You can see in the top droplet that I was a little off and the droplet is not perfectly round. It's easy once you get the hang of it!
Here is a link to them on Amazon. The label looks a little different, but same name - must be either an earlier or later version. So glad I found these!