The full SQL code will help or some screenshots using Microsoft Access.

Using built$-$in and aggregate functions, show the total quantity of sales by month.

Select the Quantity from the SalesLineItems table and the SaleDate from the Sales table. You will need to join the Sales and SalesLineItems tables.

Using the expression builder to apply a date function to the SaleDate field to display the month name only.

In the design view, click on $$Builder$$ in the Query Setup group on the Query Tools Design tab on the ribbon to open the expression builder for the date field. Expand the Functions group. Choose Built$-$in Functions. Select the Date$/$Time Category and use the MonthName and Month Expression Values.

Use the total row to group by month and sum the Quantity.