TPlink Deco M5 3xunits. Flashing blue led?

I setup the first unit as an AP. I moved to another bedroom and plugged in the second unit. All I get from the second unit is a flashing blue led.
I have no idea if it is setup.
Any ideas?


Never mind, found it, little + at top right of app, now if only it would find the freaking 2nd one!

I had to move the 2nd one into the same room as the 1st one and then the 2nd was found. So I moved it back where I wanted it. Now this location is the same place where I had an RE300 extender which had no problem extedning the signal.
I dont know whether it is the fact I plugged the 2nd unit in again, but all I got was a flashing red led. I moved it to another socket in case it was pipes or suchlike, and again, all I got was a flashing red led. I have had to reset this 2nd unit to see if it can be picked up again by the app, but I ain't impressed so far.

it seems to flash red when plugging it in somewhere else and then after a few mins it goes green.

if the instructions say that, then I missed those instructions.

Thanks.