First, make sure you have turbo mode enabled by shift-clicking the green flag. Then, regular-click the green flag once so it lights up. Press the spacebar to generate your basic random color map. Then, once the color map is completely finished, press the spacebar again to lay down the terrain. Once the terrain is there, press the spacebar on where you would like to drop your character. Your character cannot be placed onto or be moved in water. Use arrow keys for control. I recommend leaving the Variation slider around 20 to generate a nicer-looking map, but I left it enabled so you can mess around with it to see what cool effects it has.
This map was generated using something called Perlin Noise, which is a type of smooth, coordinate-based, pseudo-random variation (I know, a mouthful) that is commonly used in computer graphics. If you've ever played a game that has random terrain variation, for example Minecraft, it probably uses a similar method to generate random, but still somewhat smooth height variations. The basics of how this works is that there is a set of points on a map (mine has 20 points), each of which has two values randomly assigned, an X and a Y, making what is called vector. For each individually-drawn square in this project (there are 12 squares), there are four vectors, one assigned to each corner, that determine the internal color variation of the square. The closer you get to a corner, the more that corner's vectors will influence color, weighted according to the curve: y = 3x^2 - 2x^3 Beyond that very basic description the math gets a little more complex, but if you're curious to learn more, check out this link: https://mzucker.github.io/html/perlin-noise-math-faq.html