2 rb951 need to connect by Cabel and make one wifi

1 rb951 is in 2 floor at house connect by cabel with pppoe ether 1
2 rb951 is in 1 floor connect by cabel at ether 2

how make that two rb951 was at the same network
and WiFi was one name at both

Configure 2 rb951 with wireless mode “wds-slave” and same SSID as the 1 rb951