Hi, I attached images of how the tables look like now. I hope it's correct this time.
I added a dimensions column (shown below) in ecart then i'll just input the dimensions per item. The dimensional weight is the total of the all the items' dimensions divided by 3500.
Let's say the first item's dimensions is 6,552 (36(L)14(W)13(H)) and second one is 13,320 (37(L)24(W)15(H)) adding them up totals to 19,872 then dividing it by 3500 gives as the dimensional weight (5.68kg)
I have another question, how do I define weight classes? As you can see in my weight_class column in the shipping_rates table, weight class is numbered 1-15. How do I define that class 1 is .01kg to 1kg, class 2 is 1.01kg to 1.50 kg and so forth. Do I need to make another table for this?