WAN or LAN port when using router as access point?

So I have two netgear r7000s, one of which I want to setup as an access point and use the same ssid. The Netgear instructions say to plug into the wan port of the router to be used as an access point. But elsewhere I've read to plug into the Lan port. What is the right method and or does it matter?

Is this a good article to use?

http://www.dslreports.com/faq/11233

Tx