If the field has multiple values then they are accessible using
@{$input->{fielname}}
...or ${$input->{fieldname}}[x] ...for individual fields where x is the element.
...otherwise it will be just $input->{fieldname} for single values.
You may need to have a play to see if/how it works by just printing values.
Just submit your form and on the success page add:
print join("<BR>", @{$input->{my}});
...and see if it print all the values you selected.
@{$input->{fielname}}
...or ${$input->{fieldname}}[x] ...for individual fields where x is the element.
...otherwise it will be just $input->{fieldname} for single values.
You may need to have a play to see if/how it works by just printing values.
Just submit your form and on the success page add:
print join("<BR>", @{$input->{my}});
...and see if it print all the values you selected.