Deductions & credits

Hi the items i sell is also very hard to keep track of inventory. with that being said, does it mean that all my expenses to sell the goods should go to line 36, with 0 beginning and end inventory?

 

I also have additional questions. So if i do decide to keep track of inventory the following year and let's say i have $5000 worth of inventory at the beginning of the year. Then i decided to restock and purchase more inventory during the middle of the year. Will these expenses be added onto "beginning inventory" or does it get included in line 36?