need to allow network file share across subnets

I needed a better router/firewall for VPN access to my home office. I bought a TZ270W to help with this. I did the basic configuration successfully but I see my networking knowledge isn't as strong as I had hoped. have managed lots of routers over the years but mostly consumer-grade gear and also two sonicwalls but some years ago.

Unfortunately, the company that I would have hired to set it up has been too busy. Thought I'd do this part myself too but it's proving to be difficult.

it has a WLAN subnet 10.0.0.* and a LAN subnet 192.168.0.*. the LAN has a NAS connected.

we need to access a network share available on the NAS. because the computers on the WLAN and LAN are on different subnets, no WLAN clients can reach the NAS's network share.

I've "googled" this quit a bit. It seems I need to add add a firewall rule to permit SMB from WLAN to the NAS on the LAN.

Trying to at first get this working, I allowed all traffic from WLAN to the NAS. \\mymachine\myshare doesn't work.

I saw other users trying to do something like this. here's one: https://community.sonicwall.com/technology-and-support/discussion/937/access-internal-smb-server

I have seen some replies to similar questions talking about a dummy IP and using NAT. I am unsure how that would work...perhaps it's creating a NAT rule assigning an in-subnet address for the NAS so (back to my example) we can reach the NAS because it has an address of 10.0.0.60 that (because the MAC address is the same as the NAS which has 192.168.0.60) reaches the NAS. Despite doing some reading about this, it's not clear to me whether I should be adding this.

I had also thought I should enable SMB in "IP Helper" and create a firewall rule allowing SMB from 10.0.0.* to 192.168.0.60 (the NAS address) but that didn't help.

I'm quite surprised how difficult this has been. Can someone guide me through this?

thank you!!

mp