OK, I have no idea re YouTube video, dont bother with such things, they are usually amateur offerings, not my cup of tea
Understood entering MAC to reserve an IP No, I usually reserve a No myself, I take it you reserved a No in the Router IP No range ?
Not certain why you would have needed to use the MAC filtering though
On the GS911 WiFi, you would normally connect P2P, tell it to find SSID with scan for networks, select the right one, enter PassPhrase and save it, reboot and it should connect. The other option is to manually enter SSID and Passphrase and save it, reboot it and it should connect DHCP
I have seen some router firmware which fails to respond properly to connection attempts from embedded devices, not often but some do