@Trond_Svendsen 

Hello, sorry to tell you that the Archer C3200 does not support wireless schedule. That is to say, there is no option to turn it on and off automatically at certain time. 

While you can press the wifi button on the back manually to turn on/off the wifi function. 

In my opionin, if you want to turn off WiFi for two devices after a certain time of the day, actually you want to block the internet access of the two devices. In this way, you can use the parental control to satisfy your needs. 

Select whitelist but no keyword during the certain time you want to turn off the wifi function. Then the two devices won't be able to access internet during this period of time. 

May it help.