They have a free digi with flip flops incase you're interested, I didn't use it as I thought other DT memeber might like to use it.
For my card I masked off about 1/3 from the edge of my card base.
I use Post-it tape to mask off each layer of sea. Starting with Memento ink: Desert sand sand and Toffee Crunch.
See the video, it's easier to watch than to explain.
Then I would rip another crooked edge on the Post it and apply my sea: Summer Sky,
For my sea foam I've used white Ecoline ink, but a white gelpen or Copic white or Kuretake ink or even titanium white acryllic paint would work. As long as it's opaque. You will see the foam as it's wet will remelt the inks a little, but that helps with it blending in I think.
Basically I make wiggly lines, thin here thick there and make those bubbles. It's probably not very accurate, but the end results looks like waves to me, so that's my story;-).
I chose Memento ink this time, but this would work with any dye inks you have. Not so much with Oxides as you want them to be translucent and layer.
For the stamping I've used Memento ink Rich Cacao and the Summer set from Marianne Design. The sentiment is from Clearly Besotted (Tiny Type).
I splattered some Lawn Fawn Liquid Stardust on top from some shimmer, this time using my stamppouch to cover the white, cos you know I've emembered now lol.
For more information or to play along the AAA Cards Challenge, see this.