Hello there. I live in Turkey. I have a tv box provided by my internet provider. I was able to use this with the modem that was given to me. but now i can't use it. i canceled the old modem and i am using mi4agigabit. I installed openwrt on it. I don't know how to make settings for tvbox right now. I tried a lot but couldn't find it. I am adding the settings given for my old modem below for ıptvbox. How can I make these settings on mi4a?
Apparently the different services provided by your ISP are transported over different(ly tagged) VLANs, that's where you need to look further (and for IPTV probably also igmpproxy). Try to gather more information about the VLAN tagging (and how those VLANs are hooked up to your internal DHCP pools), both from the ISP 'modem' and local information (this information isn't just needed for OpenWrt, but also for using any non-TR069 managed ISP gear, so there should be local knowledge about these things (especially businesses usually need more capable devices than ISP branded gear)).
I'm not sure how to do this from the GUI-- but it looks like what needs to be done is to bridge (hardware switch) VLAN 103 from the modem port (wan) to one of the LAN ports which you will plug into the TV box, and have those tagged 103 packets continue on to the box. While at the same time using untagged pppoe packets for Internet from the router. The router doesn't need to do any processing of TV traffic other than bridge it through.