Using a Better Router as an Access Point and Switch

Hi everyone, I just wanted more information about this method of setting up a secondary router as an AP/switch. I currently have a slow N modem/router that is fixed far away from where I use my wireless devices. The 2.5 GHz band gives me slow wifi and has to travel a long distance to reach my devices. I want to use an AC router in a closer room to get better wireless access and use it as a switch. I also want to retain the use of my wired devices on the modem/router. From what I know, I just set the new router to AP mode and everything will work. Please let me know if you have any experiences or information about the subject. Anything would be appreciated. Have a good day!