Dont understand this thing about creating subpages

[The-Ensemble]

Creating "Subpages"

If you want to create "subpages" within your custom page, simply wrap blocks of code with the following structure:

PHP Code:

if ($_REQUEST['do'] == 'test') 
{ 
    // Block of code #1
}

if ($_REQUEST['do'] == 'test2') 
{ 
    // Block of code #2
} 


Ok.
I get some of this but not the "wrap blocks of code" part.
what code?

BTW this is a question about this hack/mod: https://vborg.vbsupport.ru/showthread.php?t=98009