@Paquito5353k 

Hi, welcome to our community.

As Deco supports wireless router mode and access point mode. My understanding lists below：

For your network topology, suppose the switches you drew in the picture are unmanaged, if Deco network works as wireless router, firstly Deco 3 must have 4 Ethernet ports(Not each Deco model has 4 ports), secondly the IP address of your client devices connected to other satellite Decos and all switches will get IP addresses from Deco network and work during the same network segment.

If Deco network work as AP mode, the IP address of all Decos and client devices connected to all switches get IP addresses are from your router and under the same network segment.

It is suggested to know more from this guide:  General questions about Ethernet Backhaul feature on your Deco