#3 What's the grammar of the script?

[Ksharp]

What's the grammar of the code section in script? below is part of my script for making installation package.

function CheckSerial(Serial: String): Boolean;
VAR
i:Integer ;
ch:char;
str:String ;
begin

i := 0;
ch := 'A';
//ch := Serial[0];
i := i + 1;
//Added by ISG Setup->Serial key field!
//i := 0;
str := 'char is' + ch;
MsgBox(str, mbInformation, mb_Ok);
Result := (Serial='ABCD-SPOT-MAUO-1234');
end;

******************************************
I want to know how to get a char from string variable?
on the above, I desired to get the first charactor of Serial by using ch := Serial[0]. But it reports error!
Can you provide me a method to achive it! Thanks!

[Nobody/Anonymous]

Logged In: NO

nobody answer me for a long time! I'm very disappointed by your support!

[Nobody/Anonymous]

I am trying to learn Pascal. It says not inside a section. Not sure how to continue.