Will a LAN splitter work?

[Dagnis]

Hello. I need a LAN splitter, at least I think that is what I require. I live in shared fibre building where phone is line coming from downstairs to my flat. I have a socket where I plug in my cable and I have internet. Now is it possible to connect more devices using something like a splitter. Basically intert this thing into socket which has two other exits, into those exits i can plug in two more devices, does that make sense? Thanks

 

[Dagnis]

This would do:
https://www.overclockers.co.uk/tp-l...rts-plastic-case-tl-sg1005d-v7-nw-174-tp.html

Assuming there's router sharing fiber into your room.
If it's more direct "bridged" connection there could be IP limit from ISP.

What kind IP address command line command ipconfig gives?
Does it start with 10.0 or 192.168?

Router downstairs is BThub and ip does start with 192.168, I also have a full access to the router with admin rights.. I assume I need a switch then. I will need to plug in this switch then take lan cable insert into socket which gives me internet then plug other side of the cable into switch, is this right? Then i add tv and firestick via lan cables as well. Will i still max out 80mbps with a switch?

Thanks.

EDIT 2 - This is how it looks downstairs.

https://imgur.com/a/lMRog0n is this a bridged connection?