Please help me answer this question . what are your variables, constrains,etc... and excel solver .... in order to minimize the total cost (opening and transport cost )

A firm from Zagreb distributes its products at the Zagreb market. The market research study shows that the firm expansion is needed. For this reason, the considered firm is planning to open two branches in Rijeka, Pula or Umag. The quantity demands, opening costs and capacities of the areas are given in the following table: Demand Capacity 15 10 Opening cost 120 150 Rijeka Pula 20 15 20 Umag 200 30 The transportation fixed cost, unit transportation cost and transportation capacities are given in the following tables. The transportation fixed cost: Pula Rijeka 1 Umag 3 Rijeka 3 2 0.5 3 2 Umag 2.5 1 The unit transportation cost: Pula Rijeka Pula Umag Rijeka 2 2.5 3 1 2.5 Umag 3 2 3 2 The transportation capacities: Pula Umag 8 Rijeka Pula Umag Rijeka 10 10 10 8 15 15 10 20 Find the optimal distribution plan (the branch locations and quantities that will be distributed) in order to minimize the total cost (opening and transportation cost)