How to add timer to a device triggered by Tuya or Smart Life

[DigitALL]

Hello friends!
I have this problem and have no idea how to solve it. Any advice is appreciated.
I have a quality air monitoring device that is connected to Smart Life.
Connected to HVAC (heating, ventilation and air conditioning) system in my home there are two devices:
1. Fresh air fan that adds fresh and filtered air in my home with a Smart Switch connected to Smart Life.
2. Ozone generator with a Smart Switch connected to Smart Life.
I wish to create a scene where when the Air Quality is polluted and reported by Smart Life, will trigger the air fan and ozone generator but for a specific time. How to stop them after a short period, regardless the Air Quality status?
So once the fan air and ozone generator are triggered, I wish to set it up so that the fan will work for 4 minutes and the ozone generator for 1 minute.
How could I do that? It seems that I can not set a timing in Smart Life.

 

[Jackie]

I suppose, "delay the action" can meet this requirement. It can perform as a timer. e.g. waiting/delay 4 minutes, then turn off the fan.

 

[DigitALL]

I have tried this one. When set for delay action, it will starts the devices after that delay but it will not be turned OFF. I need to turn the devices OFF after minute, especially the ozone sensor.