Access NAS on another local WiFi

HI,
I have a TP-Link router that is NOT wifi.

My main wifi is on a Netgear Access Point plugged into a Netgear POE switch, which is plugged into the TP-Link router.

There is also an Asustor NAS plugged into the TP-Link router with Ethernet.

I clicked on Explorer, Network, and shared network drives. It all works perfect on the PC(s) that are on the same wifi network (SSID of the Netgear AP).

I also have another router (Asus wifi) with VPN software installed on it and it is also plugged into same the TP-Link router. It has a separate SSID.

My PCs can see either SSID (but only log on to one at a time), and when I am connected to the Netgear Access Point wifi, I can see the Asustor NAS and I can map it's drives.

When I am on the SSID of the Asus Router (both it and the Netgear AP gets it's WAN from the main TP-Link router), the PCs do not see the Asustor NAS.

Is there a way to be on either router SSID and still access the NAS (that seems to be) currently on the main SSID (the Netgear AP) without exposing the NAS to the internet?

Thanks!

Keep in mind both network WiFis are plugged into the same router.

Here is the solution to my question:

Map a network drive from a different local network​

Main local network 192.168.0.x (first network router)

Secondary local network 192.168.2.x (second network router)

The NAS is on the 192.168.0.x network, 192.168.0.5 is the NAS

Open File Explorer and right click in the left pane, Network. Choose Map network drive and select a drive letter to use. Then click on Folder, and enter the \\ and the ip of the NAS. Then Browse to find the share you want to map. You may have to enter credentials. Example \\192.168.0.5

Network discovery for remote printers & file shares is based on multicast traffic, and most routers (by default) don't forward this traffic across different subnets. So you can't find new devices on a different subnet.

If routing works between the subnets, then adding a new device based on a known IP address will work.