You get ahold of your nearest wildlife management and ask them to give you the number for the trapping section ,then go from there.
I talked to one of the head personal in Nanaimo about where I wanted to trap and they sent me the trap line areas that are registered ,it shows the registered area highlighted in dark lines.
I told the personal person my email address and they sent them to me.
If there is a registerd trap line active you can not trap on there registered line ,if they give you permission then you can trap in there area that is registered ,its up to the person that has this trap line to give you the ok or the no.