Help with rollups

Hi guys. Could use some help. I’m thinking this might be where you use a conditional rollup but kind of confused on how. I have 2 tables, one with all inventory and sales info, the other is being used to rollup all of the info (items sold, total amount spent, gross amount made, net profit/loss - which subracts the 2, etc) for each month. On the 2nd table, I have a row for each month of 2019, and then each column sums up the amounts for that month. In each inventory item in the table 1, I link it to a month. Now this might be incorrect as well, not sure. I link the ‘Month Sold’ and the ‘Month Purchased’ column to the corresponding month in table 2. (There may be a better way, but i’m still learning. The problem is, it’s summing it up incorrectly because I don’t have it configured right. I want most colums (i.e. ‘Amount Made’, ‘Items Sold’) to sum up only if the value on the 1st table has the ‘Sold?’ box checkmarked. So, only items that are marked as sold. But I want the ‘amount spent’ to sum up the cost of every single item I purchased that month. Am I completely off or is there a somewhat simple fix? I’d appreciate any help. If you have any questions let me know.