Is this possible? Use 2 N900 for home network

Have 2 N900 routers. Have set up one and it is working fine upstairs. I have run cat 6 downstairs and currently have a switch installed for home entertainment devices. I would like to use the second N900(downstairs) as an access point to extend wireless coverage and to remove the switch and use the ports on the N900(downstairs).

I understand the N900 can be switched to access mode, but unsure how to set the second N900(downstairs) up without changing the settings on the first N900(upstairs)?

Do I connect the second N900(downstairs) to a laptop that is not connected to the existing wireless network, set up the router and change the device mode?

If that works, then would I connect the cat 6 cable coming from upstairs to the yellow internet port on the second N900(downstairs)?

I was lucky enough to receive a second N900 as a gift on the same day I purchased my own N900.

Any help would be greatly appreciated.

The steps on how to use the router as an access point are provide on the users manual.

You can follow the steps on the link bellow:

http://www.wdc.com/wdproducts/library/UM/ENG/4779-705072.pdf#page=71

I understand it can be an access point and understand the directions in the manual. My question is how to set up the second N900(downstairs) router without changing the settings on the first N900(upstairs) router?

I am using a laptop with the second N900(downstairs) router connected to it. When I log into 192.168.1.1 I get the router settings for the first N900(upstairs) router. 

You can change the device name to one of the routers to make sure you are not getting confused.

If the device has already been setup as an AP the computer will connect to the other router by default.