Hi,
Welcome to Perl!
Delaring variables can be done at the beginning of your program/code or at the point where you being to use those variables in the code.
For example,you may declare varaibles at the beginning of your code as in -

#!/usr/bin/perl

use strict;
use warnings;

my $variable1;
my $variable2;
...
...
### Rest of the code follows from below
...
...
### End of the code
[download]

Also, if you are declaring variables close to the point where you begin to actually use them, you may do something as below:

#!/usr/bin/perl

use strict;
use warnings;

....
....
...
for (my  $variable1=0; $variable1 <= $#someArray; $variable++) {

### Do something here

...
...
}

...
### Rest of the code here
...
[download]

Best Regards,
garbage777