Since this is a Scratch mish-mash of KSP and SFS, the controls are somewhat complex. Controls can be seen and set in the Settings menu. As for how to play, build a rocket, and go up, simple as that! There's also a Career Mode for those interested.
TurboWarp link: turbowarp.org/782029398 Ever wanted to build your own rockets and fly into space? Well, now you can! With over 30 parts to pick from, you can make anything and go just about anywhere you can think of! Features: Staging, astronaut, satellites, colonies, interstellar travel, and actually good physics! Is sandbox not to your taste? Well, why don't you try Career Mode: a progression-designed mode that slowly teaches you to think outside the box. Inspiration from both Spaceflight Simulator and Kerbal Space Program, I highly recommend playing them.