@Ufin 

Deco will use Ethernet connection when it can, switching to WiFi only when it can't. This TP-Link FAQ document may help you to figure why your Satellite Deco can't use Ethernet link: General questions about Ethernet Backhaul feature on your Deco

  @Alexandre. Thanks alexandre. Can you help me understand 

1) does the topology in picture one mean I have to use first Ethernet port on main deco as incoming and second as out cable to next deco satellite

2) does the picture two for star topology mean I have to use on main deco one of the Ethernet port as incoming from modem and second port as outgoing to switch itself 

min other words 

currently I had modem/router from mikrotik connected to switch, and thee deco satellites on switch.

3)  in the article it refers one satellite as router. Is it equivalent of "setting main deco" in application 

  @Ufin 

If your Deco setup is as following:

then I would recommend to configure Deco mesh to run in Access Point mode. That will make all Deco nodes use Ethernet for backhaul. See How to set up Deco to work in Access Point mode