To create a circuit, you have to do this:

circ circuit_name(arg1, arg2...)->{what the function does}

circ is the circuit "declaration", and everything after the -> is interpreted as code.

Normal circuits have 1 bit as output, but if more bits are required, use the + symbol to separate bits, like this:

circ circuit_name(arg1, arg2...)->{1st bit}+{2nd bit}+...