You have 2 powerline boxes.

I would plug each into a power socket that are close to each other, to save you walking all over. Although the manual says do not use a multiblock extension I find you can for setting up.

So with the 2 units plugged in, wait unti the lights stop flashing and all looks stable then on the side of each press the button above the lights for about a second or two.

Lights should flash and will eventuallt stop flashing.

Now unplug the units and plug them in where you actually want them.

All the lights should be solid, now plug in your cables and all the lights should go green.

Now all should be connected.

Download and install the latest TPlink software, run it and this allows you to name your devices so you know which is which (might have to turn one off to work out whch is which), then you can set up your wifi