I don't fully understand it, so it figures I wouldn't know wth digits is for. I just used the other media sites as examples and they were only using $id lol
when I was said 'Advanced options Tab--> Use 'Match URLs' as PCRE regular expressions: checked'
for future reference I was referring to this(if you are using the match expression that Brogan posted you don't use this as it is not a regular expression)