Workflow rule condition in ODM

When defining condition for workflow campaign, how to set condition for the rule (2nd part in condition)? Example: select email link clicked as the rule and then in set condition for this rule part, select 'website activities', average time spent , and then there is another field called 'restrict by' - how does this work? If I select sitre referer URL there what should the URLK be? This is not in the help document. Where can i find more info regarding this second part for rule condition? Will the first part 'email clicked' will be considered always or that rule plus