How to register m3u channel list in a set-top box for TV? + Newbie questions about working with the prefix?

Question

A television

Greetings.
I'm going to take an IPTV set-top box from a friend, but I haven't figured out how it all works yet. In short, how does everything work?
As I see it (simple setup of the set-top box for TV):
1) I take the set-top box, turn it on, connect the Internet from the router via LAN, plug in tulips / hdmi.
2) On the console in the menu, I prescribe the address to the m3u sheet with channels. For example this one .
3) I take the remote control, sit on the sofa and stick into the zombie.
And now the questions?
Does the prefix depend on the provider (a friend gave RTKashnaya, but I have domra)?
Does any set-top box support m3u or do they have a different format "by default"?
What is the minimum internet speed required for normal HDTV viewing?
Do I need to additionally configure the router for the set-top box to work (port forwarding, etc.)?
I ask you to explain "in your own words" without Wikipedia, etc., with wireless equipment on "you", but somehow I did not come across such prefixes.
I didn’t find the IPTV tag or something like that, if I put it wrong, please fix it.

Answer 1

2) On the console in the menu, I prescribe the address to the m3u sheet with channels. For example this one.

99% of such a menu will not be possible. In addition, providers, as a rule, do not provide playlists or generally broadcast as a broadcast, roughly speaking. In addition, providers can also block by mac set-top boxes or use smart cards \ cam modules. In addition, they can also broadcast in their own format purely for their software on the console.

Does any set-top box support m3u or do they have a different format "by default"?

based on the answer above, yes, everyone has everything by default, and in their own way, incl. for each operator.

Do I need to additionally configure the router for the set-top box to work (port forwarding, etc.)?

Again, see the answer above, most often yes, in addition, the router stupidly may not be able to igmp or vlan. In addition, operators do not give information on what exactly needs to be opened, turned on, configured, and they put their routers / switches without the ability to change settings.