Comments are ignored by the compiler. You should use comments often to explain your program. After a few weeks you don't write on a program, you can easily forget which function did what. You can easily declare the parts of the program you don't need as comments. The second way to make comments need AmigaE 3.0 or above.
Every procedure can call another procedures.
PROC must be uppercase, because it is an keyword nameofproc you must give every procedure an unique name. Every procedure can have parameters. These parameters must be enclosed by parantheses behind the name. Every program must have a procedure with this name. The procedure main is called automatically when the program is started.