Even if you have nothing to report this quarter, you still must lodge a nil activity statement.
The easiest and fastest way to lodge is online. Simply select the ‘Prepare as NIL’ option on your activity statement form and you won’t need to fill in each label as a zero.
You can lodge online through the ATO business portal or through your myGov account if you are a sole trader. Read more https://www.ato.gov.au/Newsroom/smallbusiness/Lodging-and-paying/Nothing-to-report-on-your-activity-statement-/?sbnews20180411