You have 1 SH, (the black box), it has to 2 WIFI feq (2.4GHz and 5GHz). The SSID is the same unless you change it.
I myself when i set my mums up, changed the SSID to VMxxxx for the 2.4GHz range, and VMxxxx_5G for the 5GHz range.
Bost moden devices use 5GHz, its faster.
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Red (VM SH2 AC Beta tester)
Running on 1Gbps VM service with SH4 in Modem Mode, with a ASUS RT-AC5300 router. With this setup I get Fantastic WIRED and WIRELESS Signals in my home. I dont work for VM. But I work in IT, and I know my tech.
My advice is at your own risk. If you are happy with my answers please press Kudo ?