You're not alone the PTO run feature on the newer Workmasters can be a little confusing at first. On your 2023 Workmaster 75, that small button on the dash is indeed key to keeping the PTO engaged when you're off the seat.
Here’s the general sequence:
Start the tractor and engage the PTO using the lever beside the seat like you normally do.
Before leaving the seat, press and hold that small PTO button on the dash until the PTO light starts flashing (usually takes about 5 seconds).
Once the light is flashing, you can safely get off the tractor and the PTO will continue to run.
This is a stationary PTO feature, meant for use when you're off the tractor but the machine is stationary like when checking a baler or running a grain auger. If you try to move the tractor or do anything else while off the seat, it’ll kick the PTO off.
If the light doesn’t flash or the PTO shuts off when you stand up, check that your seat switch is working properly — if the tractor thinks you’re off the seat prematurely, it won’t let the sequence complete.
Hope that helps!