how do i find these two step for step?

Required information [The following information applies to the questions displayed below.] Alexandra's Boutique has the following transactions related to its top-selling Guccipurse for the month of October. Alexandra's Boutique uses a periodic inventory system. Required: 1. Calculate ending inventory and cost of goods sold at October 31, using the specific identification method. The October 4 sale consists of purses from beginning inventory, the October 13 sale consists of one purse from beginning inventory and two purses from the October 10 purchase, and the October 28 sale consists of three purses from the October 10 purchase and four purses from the October 20 purchase