Synthia 2.0 works as an instrument out of the box, and coding it is optional — but it is where the second half of the fun lives.
Start with CircuitBlocks at code.circuitmess.com. It runs in a desktop browser — Chrome, Edge or Opera; Safari and Firefox cannot connect to the hardware — and you build programs from drag-and-drop blocks while it writes real MicroPython underneath. The beginner-friendly Synthia coding guide at circuitmess.com/blogs/resources walks you through the first project.
Two things worth knowing before you start
Your program runs from the device's memory and clears when it resets. That is by design — your sketch stays saved in your CircuitBlocks account, and you press Run again after a power cycle. The detail is in Why doesn’t the program I wrote in CircuitBlocks stay on the device after a reset?.
You can always go back. The Restore firmware button in CircuitBlocks puts the standard instrument back exactly as it shipped, so nothing you try is permanent.
Ready for more? The advanced routes — typing MicroPython directly, or moving to C++ — are laid out in What programming languages can I use with CircuitMess kits?.