got sent 2 TP-Link Deco X20 when i renewed my plan with VF

is it posable to use my router ( ultra +) as the main wifi and setup the 2 TP-Link Deco X20 as AP ?

all i can see in the manual you have to use a ethernet cable  to the router with 1  TP-Link Deco X20 the have the other 1 else where

other words connet the main deco to the router over wifi not ethernet