What solution or method would I use to find this answer? I'm very confused by this chapter in the book.

Q.) Suppose the following table provides the production possibilities for the only two countries in the world. These two countries can produce only these two goods. Assume resources are identical in production. Use this information to show how trade benefits the world and the two individual countries. Also assume the countries are able to produce with no idle resources and no production mistakes (Use a ruler to draw PPFs, you only need two panel (one for each county) to answer the entire question).

Australia has 180 Silver and 270 Diamond

Canada has 180 Silver and 90 Diamond

b)Show the actual production levels of each country assuming the countries are selfsufficient and don't trade with each other and allocate half of their resources to the production of each good. Label this point a on the graphs.