Welcome @DARR_Tech,

Hmmmm, I'm not sure you know enough about how this all works, yet, to set things up successfully on your own.  In a nutshell, here's what you'll need:

1) Broadband connection (business cable, FFTH, DSL, etc.) at each location.  Generally speaking, these broadband services "come with" a router.  This router provides firewalling, NAT, DHCP, routing, DNS lookup/relay, etc.  Often routers have a small Ethernet switch built in (though they usually only have a small handful of LAN ports or even just one).  Sometimes these routers (SOHO) also have a Wifi Access Point built in.

2) Depending on the size of the location, and assuming you are going to turn off the Wifi in the router (if it has any), you'll need multiple, Ethernet connected access points wired back to the router, or wired back to a larger Ethernet switch which is then uplinked to the router.  It's not uncommon to deploy one AP for every 1000-2500 sq feet.  But the specific number required will depend on the number of users, how the space in confgured, walls, etc.

3) The AP's will need power.  Most / all business class AP's use PoE.  You will need a large enough (ports and power budget) PoE switch to power them all, or you will need to use the included mid-span PoE injectors.  Ethernet can travel up to 100m (Gigabit over Cat 5e and higher), but PoE does not travel that far.  Only 40-60meters.

4) You will need a voucher system for the fee for Wifi access model you have described.  You'll need to use the Omada SW or OC-200 / OC-300 to support this.  These will need to be running 24x7.  There are also 3rd party voucher solutions, I believe.

5) Best practices would dictate that you keep your "public" (for customers) Wifi and wired networks separate from your "private" (business) networks for security.  You would not want unscrupulous customers hacking into your POS and financial systems, right?  This can be accomplished using VLAN's -- essentially virtual network separation.  But VLAN configuration is a fairly sophisticated setup.  Alternatively, you could just keep the networks physically separate -- separate broadband connection, separate router, separate switch, etc.

You can check out featured stories and case examples for TP-Link, here:

https://community.tp-link.com/en/business

-Jonathan