Iterations

Hello Community! 

Could someone explain to me how iterations work in Workfront? Is it for projects or tasks?  and if we add say Sprints/Phases phase-1 ( add XXX scope), Phase-2 ( add YYY scope) and then how can we assign milestone path and apply? As of right now I can only apply milestone path GO LIVE once to one task. How are you guys using iterations and would you guys have any recommendations for using iterations for sprints/phases? I would like to be able to see if I can assign scope1 and scope2  GO LIVE dates with GO LIVE Milestone path. Essentially I would like to know how you are guys are assigning the same milestone to more than one task.