@Natducati This is possible.  There are various ways to achieve that, depending on your expectations and the configuration of your house.
 

Do you have an ISP modem?

In all cases:

- the main Deco must be connected by Ethernet cable to a device giving access to Internet

- the Deco mesh will broadcast its own wifi, it will not extend the wifi of the Archer router

  @yves_b Thankyou for the reply.

What you describe is what I have ended  up with. The main deco is now connected to a ethernet cable and the satelilgihts are connected to the main Deco.

I do have an ISP modem.

I decided to use the Archer as thought this would give me greater speed .

Thanks