A rostered day off (RDO) is a day in a roster period that an employee doesn't have to work. It can be paid or unpaid, depending how RDOs are set out in an award or agreement. When RDOs are paid, it it because an employee has accrued extra hours that add up over a set period of time and this is taken as an RDO.
When building the rules, enter the conditions that trigger RDO accrual (e.g. after 7.6 hours worked per day). If there is a maximum amount of RDO that can be accrued (e.g 0.4 per day), this can be set under After number of hours worked > Advanced Options.
Then, under outcomes, ensure the rate has been entered as '0' and 'Export this time as a TOIL or RDO accrual' has been ticked. This will ensure the hours are considered an accrual and will not be paid. Hours will be paid when RDO is taken.
In the above example, relevant staff will start accruing RDO after 7.6 hours worked and will accrue a maximum 0.4hours of RDO if they work 8+ hours (7.6+0.4 = 8). If staff work less than 8 hours, they will only accrue the difference between hours worked and 7.6 hours. If you'd like to ensure they get the full 0.4hours of RDO accrual even if have not worked the full 8 hours, you can duplicate your RDO rule and add a condition that pads the RDO accrual to 0.4 by entering a condition under Minimum shift length.
A 'RDO Taken' leave type can be created at https://my.tanda.co/awards/leave. Generally this leave would be considered 'ordinary' hours and cost at a 1.0 pay rate multiplier.