How is the W1 figure calculated in my BAS report?
The W1 is the total gross wages/salary payments from which you are usually required to withhold amounts.
For more information click on the following ATO link https://www.ato.gov.au/Business/Business-activity-statements-(BAS)/In-detail/Instructions/PAYG-withholding---how-to-complete-your-activity-statement-labels/?page=3#W1Totalsalarywagesandotherpayments
To set accounts to be included in gross wages figure for the BAS return:
For example: