A first Musi program should show the shape of a real file: import what it needs, name a value, and export the part another file or tool can call. The goal is not to memorize every form. The goal is to see that a Musi file is mostly a list of declarations that can be read from top to bottom.
let answer := 42;
answer;The example is small on purpose. It has the same bones as a larger program that prints a shipping label, prepares a pet feeding schedule, or checks whether a meeting room is free. There are names for data, there are expressions that make new values, and there is one exported entry point.
What to notice first
Look for let before looking for clever syntax. let introduces a name, and the rest of the line tells you what value that name receives. When a declaration is exported, it becomes part of the file's public face. When it is not exported, it is a helper for this file.
Growing without losing the thread
The next useful change is usually another named helper, not a larger expression. If a line starts to describe three ideas at once, give one idea a name. A receipt formatter might split subtotal, tax, and message; a game rule might split canMove, nextSquare, and winner.