I am having a really hard time understanding how to use solver.

A manufacturer company is considering transporting products from 5 different regions to 5 different markets. Instead of setting up a facility in each egion, they want to consolidate plants in a few regions. Although it improves economics of scale, it will increase transportation cost and duties. There are variable production, inventory, and transportation cost (including tariffs and duties) of producing in one region to meet demand in each individual narket demand. Fixed cost is also associated with facilities, transportation, and inventories at each facility. The company is considering two different blant sizes at each location, low-capacity plants and high-capacity plants