Can you explain this step by step?

Calculated Fields

You will build on the data stored in the Model by creating calculated fields to summarize and enhance the

data on reports. The crucial calculated field will be a subtotal for each record in your joining$/$bridge entity

$($this may be called items, line items, orders or something else depending on your own data model$).$ The

subtotal will factor in the unit price of each product in your store, as well as the quantity of each product

purchased in a sale.

If you added Quantity as a field on your joining entity, you will have what you need to finish this step.

Otherwise, you may need to first create a new field on your joining entity to store Quantity. HINT: If you

have already created a significant number of records in your joining entity, you may want to export the

existing records to Excel, populate the Quantity field using the RANDARRAY function, and reimport your data

rather than updating records by hand.