For this zap, you need to execute a trigger every time that an order is placed, if you don't know how to do it please take a look at the following article.
Now we have to create the action which time will be Google Cloud Printer and select as Action the only one that will show called "Submit Print Job"
Add the Google Account where your printers are, Zapier will ask for some permissions to see them allow Zapier to do it and continue.
Edit the Template of how the Print will look.
Set up all the fields according to the way you need it to be, it's up to you.
Click on continue to see how it would look.
Test this app, click on Create & Continue & that's it, you have it integrated now, the orders should be printed right away on your side.
Let me know if you had any doubt on this Article or if you have any recommendation
Have great printing & Ordering.