I am trying to recreate the landscape in this image but I am having a very hard time knowing where to even start. Any suggestions appreciated!

This can be done with an elevation function EF(x,y) = z. Given a domain 2d like a rectangle or a surface, you sample N x M points and evaluate each with an elevation function that gives you the amplitude of movement of that point 2d (usually in the normal direction of the domain). This function can be done in multiple ways, but basically you can use distances, like the distance from each sample point to a influencer point or geometry, and modify that value using parametric functions like sin(d) or exp(-d^2/w^2) and also some remap to scale it back to your domain.

Thank you for taking the time to write this out. In don’t understand in practice what this definition would look like. If you are willing, I’d appreciate a definition example using the above formula.

I’ll take that as a no