[Users] Avpops tutorial

Hi everyone, I'm a newbie when it comes to AVPops, so please bear with me. Am looking at the avpops tutorial , when i came across this web : http://www.voice-system.ro/docs/avpops/ar01s08.html#ex_bitmap_acl It teaches you how to use make use of avpops to create a bitmap acl. For the whole of the website, nothing was done to explain to you what each and every of those commands and the values in it are for. It just doesn't make sense to me ?! For example , they said place this in :- modparam("avpops","db_scheme","scheme0:username_col=username;domain_col= domain;value_col=acl;value_type=integer;table=subscriber") modparam("avpops","avp_aliases","acl=i:800") Can i ask what these 2 lines are talking about ??! Please help explain to me how to use that bitmap acl ! Anything that we need to change at the database? Thanks alot! REgards, Sam