Combining or "Daisy-Chaining" - Multiple Devices, Part 1

It's commonplace to - "Daisy Chain" - several of these devices in series. For example, if you were to obtain single-function boxes for all of the above functions, you could hook them all to one another like this:
WiFi Distribution in 5 Separate Modules
That basic, logical flow (Modem, Router, Ethernet Switch, WiFi Access Point) is retained regardless of whether the functional lines are contained within 4 separate network boxes, or in a single box.

Here's an example of that same functionality housed in 2 separate boxes:
WiFi NOC in 2 boxes, version 1

Modem, Router, and Ethernet Switch
2- Wireless Access Point.

Here's an implementation of the identical WiFi distribution architechture in 3 boxes:
WiFi Distribution Setup in 3 Boxes

2- Router and Ethernet Switch
3- Wireless Access Point