I have one Powerline adaptor TL-PA4030 and two Powerline extenders AV500, bought many years ago.  I lost the instructions ages ago but now need to set them up with a new (not a TP-Link model - sorry!) router.  None of the online threads seem to exactly match what I've got.   One TP-Link video tells me to (1) plug in the adaptor, then (2) plug in the extender, then (3) press the clone button on the adaptor and then (4) press the WPS button on the router.  The video says nothing about pressing any button on the adaptor (the only button thereon being 'pair').   The video also says wait until the clone light on the extender starts to flash slowly.   However it goes on flashing quickly, never changing to slowly.

Does anyone have any 100% correct and 100% clear instructions for a non-techy like me, as to how to set up this combination of adaptor + extenders?