Subnetting into 2 Networks

We have a coffee shop that we want to have access to wireless internet, but we don’t want those accessing the wireless to have access to our business LAN. Will placing a wireless router in the coffee shop and putting it on a subnet give us what we want?

We are using an AdTran Netvanta 3200 router for the WAN connected to an unmanaged 24 port Netgear switch and then to the Netgear wireless router that I would like to be on the separate subnet, but have internet access without having access to the LAN (the other part of the network).