Determine the genetic map of the recipient | Homework Help

Suppose you have a set of four Hfr strains and you carry out a series of crosses with a multiply marked recipient that is auxotrophic for many different nutritional markers. you do interrupted mating experiements and find the following results concerning which markers are transferred to the recipient from each of the Hfr strains at various times:

Hfr1: Lac at 5 min, Leu at 12 min, Pur at 14 min, Thr at 22 min, Ile at 30 min, Val at 45min
Hfr2:Thr at 5 min, Pur at 13 min, Lac at 22 min, Cys at 30 min, Met at 40 min, Ala at 60 min
Hfr3: Val at 5 min, Ala at 20 min, Met at 40 min, Cys at 50 min
Hfr4: Ala at 5 min, Val at 20 min, Ile at 35 min, Thr at 43 min

Determine the genetic map of the recipient and show the point of origin and direction of transfer of each Hfr strain…. this completely confuses me.