Connection in a lan network, so that the Internet is available through the ether

I warmly welcome,
It will be more pictorial, but I hope it will make it easier to find a solution.

1. such a wire comes into the apartment
2,3,4 such cables go to individual rooms, but the entrance is, as you can see, only telephone
and the output is as follows

i.e. I have a computer telephone socket.
I have a connection from 1 to 2 - there is a funbox in this room.
I have two questions: first, what is the purpose of such a solution that suddenly a telephone cable becomes a computer telephone, it does not allow for the current configuration of computers into an Ethernet network?
Second question. What and how should I connect to be able to use the Internet via LAN in another room?

Fanbox to room 1 and the distribution of sockets to LAN rooms should be prepared.

Return the ethernet network from the funbox to the cabinet where you have a switchboard and install a switch there that will divide the network into the other two rooms.

jimasek wrote:

Return the ethernet network from the funbox to the cabinet where you have a switchboard and install a switch there that will divide the network into the other two rooms.

Hi, thanks for the answer, but I don't understand this solution. What do you mean by "going back" with the ethernet network to the cabinet? In the cabinet I have a cable that 'comes' from the operator - socket 1 - rj11, for me this socket is connected to socket 2 so that the funbox can stand in room 2. In each room I have a socket as in the second photo, i.e. I can insert rj 11 and rj45 (but in the switchboard I can only put on rj11). I would have to have a switch with rj 11 inputs to split the signal to the rest of the rooms, but it doesn't exist? The second option would be to break these inputs in the switchboard from rj 11 to 11 and 45 separately, but I would prefer to avoid it, because I have never done it before.
Edit ---
Now I checked and both the RJ 11 and RJ45 cables come in this socket in the cabinet

But looking at the picture, you have a separate twisted-pair cable in the room with two LAN sockets and a telephone. So if you don't want to interfere with this installation yourself, ask someone for help. And connecting the rest.

whda wrote:

The second option would be to break these inputs in the switchboard from rj 11 to 11 and 45 separately, but I would prefer to avoid it, because I have never done it before.
Edit ---

Here you have no other option, unless you move the funbox to the switchboard. You already have it done in the socket, I don't know what it looks like in the switchboard from the back because you can't see it in the photo.