My guess is you can not. This is one of those read the manual and see if it has the repeater feature or not. It used to be very uncommon and is not still not common on lessor known brands and lower end routers.
It either has the feature or it does not. Even if it does placement is very critical. It must be placed in a location it gets strong signal from the main router but can also provide a strong repeated signal to the remote room.
Now if have ethernet cable to the back of the house you can use the device as a AP. Many routers have the feature but you can search how to use a router as a AP, there are even youtube videos.
If you do not have a ethernet cable if you have Coax cables you can consider MoCA or you could look...