Using an old router as a NAS through WiFi

Hello guys.
I've been trying all day long to setup my old Mi 3G with OpenWrt as a NAS in my network. I already did it before and it worked, the problem this time is, this NAS server has to be connected through Wifi and not through cable.

What I used to do with the cable connected was just setup the Mi 3g as a Dumb Ap and configure samba. His SMB server was shown to every device in my network.

This time I did the same thing, but now I can't connect with through cable so I connected my 3G in my 5GHZ wifi in the wireless interfaces > scan > add.

With this last configuration I can't see the smb server in the network and I can't even acess openwrt web page.

Can you guys pls help me out? I'm struggling a lot.

I'm kinda noob and this may be a very easy thing to adjust but I really dont know what else to do.

Is the client wifi a separate interface, or are you trying to bridge it to the lan? Bridged client doesn't work in most of the routers, I think only a few of them had a chip which allowed it.
If the AP supports WDS, then a WDS client can be bridged. Otherwise you'll have to create a new interface, say wwan , assign the client wifi there, and also assign it to lan firewall zone.

Sorry friend, I didn't got it. Can you explain it again?