Your bank will typically issue you a batch of check stationery for each bank account. Each batch will have a sequence of check numbers with a start and end number. ActionStep keeps track of all the checks in each series and records which check numbers have been used, voided, or are available for printing.
The first thing you need to do to enable check printing is to register the pre-printed check series you currently have on hand. To setup a new series go to Admin>Accounting>Check Series and select Create Check Series.
Enter the details for the series and upload the check template. 
Once you have uploaded and saved a template you can generate a quick preview to see if it has been setup correctly and line it up with a photo-copy of one of your pre-printed checks. 
TIP: Use 'Preview' to test your check templates