Follow the instructions and all will become clear. This will allow you to input your own polynomial based on its degree and coefficients, and will then solve it like the boss it is. Complex numbers will be added later. Like in the next few years, at most.
Utilises the Alberth method to determine roots. Scratch (and javascript) have an inherent issue with numbers, so this system rounds to 10^-13 to escape issues with the method never converging, before rounding to 10^-12 to prevent an abomination like 5.0000000000002 ever happening.