Average check calculation by months for 2019

You have a table with data on orders for the years 2019‑2020. It is required to calculate the average order value for 2019, broken down by months.

 uuids — Customer ID
 order_dates — Order date
 orders — Order ID
 order_values — Order amount
 order_sources — Platform
 mail_ids — Store number where the order was placed

You need to write a query that groups the data by months and shows the average check for each month of 2019.