Turning your FreshTomato router into a switch or Access Point (AP) is fairly easy. In FreshTomato, the difference between using your router as a switch versus using it as a Access Point is only about making use of the router wireless interface(s) while using it as a switch. In other words, you first have to turn your router into a switch and then it can be used as a Access Point by adding a Access Point in the Basic > Network setting page.
To turn your router into a switch follow these instructions:
Then link your routers with an Ethernet cable plugged into any one of the LAN ports on both routers to create a LAN to LAN connection. On the router you want to use as a switch, you can use the WAN port if it was reassigned to the LAN bridge.
Make sure every port is assigned to the same bridge (e.g. br0) in Advanced > VLAN on both routers.
First turn your router into a switch following the instructions above, then to add an Access Point you only need to add them in Basic > Network like you normally do when using your router normally. Additional AP can be added using virtual interfaces in Advanced > Virtual Wireless.
Make sure every ports and every wireless interfaces are assigned to the same bridge (e.g. br0) in Advanced > VLAN.