I need help on where to begin!!! I am struggling with this question.

Inventory Valuation Dunn Company's record of transactions concerning inventory for the year was as follows. Compute the inventory at December 31 on FIFO basis. a Calculate ending inventory in Units. First-in, first-out (FIFO) Ending Inventory Calculation - Units Beginning Inventory in Units: January 1 30,000 Use linking to pull number from chart above. See this for example. Purchases: \begin{tabular}{lcr} \multicolumn{3}{c}{ Sales - Total Units } \\ \hline February & 4 & 4,000 \\ March & 3 & 6,000 \\ August & 2 & 3,000 \\ October & 12 & 20,000 \end{tabular}