RT-AC88U Set as AP, How do I get into it to check settings?

[JOE.G]

Hi,
I have the above router out at my Shop set as a AP, it gets it's signal from a Nano station. Only think hard wired to it is the Nano station and my DVR, everything else is wireless. At some point I plan to up grade main router in house and probably replace 88 U with current house router. I would like to go into 88 U to take screen shots ( I really know basic stuff ). If I connect laptop directly to router and login into admin page it takes me to the main router.

 

[Piotrek]

Use IP address RT-AC88U (AP) to login.

 

[JOE.G]

How would I find that? I found one next to router in main page but it just brings me back to Main router page, Do i need to be plugged into AP?