Write WordPress plugin called "studiou-wc-ord-print-statuses" in PHP, that extends WooCommerce plugin.
Plugin will have following features:

1. Extends Order status aligned after status wc-processing:
	wc-to-print - Prepare to Printing
	wc-in-print - In Printing
2. Extends Order fields (add new fields):
	to-print-date (DateTime) - Prepare To Print Date
	in-print-date (DateTime) - In Print Date
	external-ref-ord-no (varchar) - External Order Number
	external-ref-ord-delivered (DateTime) - External Order Delivered
	
3. In screen WooCommerce/Orders in combo near "Search Order" button there will be allow to find orders by field external-ref-ord-no
	
4. In screen WooCommerce/Orders extends (add new options) combo-box Bulk Actions for actions:
	Prepare to Printing Export
		- export all selected orders by using custom sql "SELECT * FROM `vsu_orders_car_prod_qty_img`" to .csv file
		- set all selected order statuses to wc-to-print and set order field to-print-date to current date.
	Set Status to Prepare to Printing
		- set all selected order statuses to wc-to-print and set order field to-print-date to current date.
	Set Status to In Printing
		- set all selected order statuses to wc-in-print and set order field in-print-date to current date.

5. In screen WooCommerce/Orders overview grid add columns (at the end) for new fields to-print-date, in-print-date, external-ref-ord-no
		
6. In screen WooCommerce/Orders add button "Import InPrint protocol" that will do (after press):
	- Import .csv file from local disk.
	- Import file will have following columns: "Order No", "ExternalOrder", "ExternalOrderDate"
	- Distinct values from import file by column "Order No"
	- Update all Orders in database, defined by column "Order" No and set order status to wc-in-print and set field in-print-date to current date.

7. In screen WooCommerce/Orders add button "Import Delivered protocol" that will do (after press):
	- Import .csv file from local disk.
	- Import file will have following columns: "Order No"
	- Distinct values from import file by column "Order No"
	- Update all Orders in database, defined by column "Order" No and set order status to wc-completed and set field external-ref-ord-delivered to current date.