
Creating a single Eero network

Hi there,
I am trying to create a single wifi network using my 3 eero 6+'s and one eero.
As illustrated, currently i have two wifi networks, one in the garden office and one in the house.
I want to make these one network, and I understand that this is possible even if the eero is out or range from the others provided it is connected using an ethernet port.
My eero app always displays an error stating the eero is too far out of range, even with ethernet plugged in.
I know the cables and hardware are fine because I get good speeds as two networks.
If anyone is able to help me please! Bought them with the intention of one network and have been trying for a couple of weeks now and can't seem to figure it out.
Thanks
L