The man page you show is for if your provider uses a VLAN (ID) for your WAN connection (as well as interface/port setup for VOIP and IPTV), this is not what you want. So you don't need to select a profile or contact your ISP. If your internet/VoIP/IPTV has been working there is nothing you need to do.
For network separation using a single internet connection, you would normally use a VLAN (switch) in combination with a firewall (e.g. pfSence) which allows the separate networks to access the internet (your router) but not each other. Schematically it would look, for example, like this:

Addition:
As Tom Yan suggested, there might be another item in the config menu of your router. If not, your router does not support sharing one internet connection while separating the networks (ports). Or as JW0914 suggested in his comment use OpenWrt if your router is compatible (some manual configuration might be necessary though like setting up the VLANs, subnets, firewall rules, etc., not sure if OpenWrt can do this "out of the box", unless you can use s.th like a guest network, etc.).
PS. A big leap (and this shouldn't work) try to set different VLAN IDs for interface/port 3 and 4 (untagged), for example, 100 and 200, that should separate them from each other but (hopefully) they still will be able to access the internet (probable not since you would have to set a VLAN ID to the WAN port as well).