Procedure Examples VR7.1

Been trying to learn procedures, and having some difficulty. After reading
examples online, I've found myself going in circles and even more confused.
I feel like I'm throwing knifes in a dark room...

I'm attempting to create a very simple procedure that converts a given
numeric value into another. In this case, a value in Celsius to be
converted to Fahrenheit.

I can't seem to get my PR and PI sorted out, and/or the positioning of the
P spec decs. Do I create this as a module, or a bound program? Please let
me know what I am doing wrong. I would like to understand how to properly
use a procedure so I can extrapolate this simple example into larger ideas.
(Machine is 7.1 version of the OS)

HDFTACTGRP(*NO)
HMAIN(C2F)
D CVT2F PR 5S 2 EXTPROC('C2F')
D
D $C 5S 2 VALUE

D$F S 5S 2

/FREE
$F = C2F($C);
DSPLY $F;
*INLR = *ON;
/END-FREE

PC2F B EXPORT
DC2F PI 5S 2
D $C 5S 2 VALUE
D$F S 5S 2
/FREE
$F = (($C * 1.8) + 32);
RETURN $F;
/END-FREE
P E

Thanks in advance!