To create a new schema file, click New in the toolbar or navigate to File > New Schema File. A tab titled 'Untitled1.asn' is displayed in the central editing area of the GUI.

Define the schema by copy/pasting text or by manually entering text between the "DEFINITIONS ::= BEGIN" and "END" statements in the file. When finished, click Save file in the toolbar or navigate to File > Save file or File > Save file as. Click Validate to check for proper syntax and to confirm that no errors are present. Upon validation, a success or failure message is returned in the Error Log.