Easiest way is to (adjust pos($yourstring) if needed and) do a scalar match with the //g or //gc flags. Untested:

# find word
if ($string =~ /\bword\b/g) {
   # skip forward from end of word 12 characters (just an example)
   pos($string) = pos($string)+12;
   # skip forward over whitespace and grab 5 digits:
   if ($string =~ /\s*(\d{5})/gc) {
       print "here are your digits: $1";
       # now pos points to after digits
   } else {
       # pos is unchanged (due to /c flag); try something else
   }
}
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