If the third lights from the top of the powerline plugs are not on, then the units are not paired. To pair the power line plugs, do the following :
1. plug both power line plugs into the mains.
2. On the smaller power line plug, press and hold in the paring button for 5 seconds, then only once you have done that, do step
3. On the larger power line plug ( which has the wifi transmitter ) press and hold in the paring button for 1 second.
4. eventually after a bit of flashing, both lights should come.
How to confiture your tplink wifi without installing anything on your pc.
You can not connect to a built in web configuration page on the smaller power line plug, as it does not have one, but you can on the larger (wifi transmitter)
on the mac:
1. Unplug the smaller powerline plug.
2. Plug in the plug in larger power line plug.
3. Use the ethernet cable to connect it to the computer
4. On the mac, go to network in the control panel.
5. select MANUAL
6. set the ip adddress to 192.168.1.100
7. set the subnet mask 255.255.255.0
8. open in a web browser - http://192.168.1.1, then you can set up your power line wifi.