Have An Abnormal Network Setup.

[chewtech]

Hi there! So I have an abnormal setup with wireless. To start with, this apartment of mine is kind of a ghetto rigged car lot, with it's sales offices, and two apartments above it, all of which sits in a barn. So both apartments are around 1100 square feet. And for the longest time, our neighbor has worked at TWC, so we got cable with all premiums, movies half off, and the best 300mps internet package for just paying him 15 a month, which is impossible to beat, and we kinda just went along because that was so cheap. Well they moved out and we're wanting to, to to save money for us buying a house, we figured we'd go the same route again and kinda just get internet and cable at the normal places, but kinda share amongst the building to then split the bill, so 100mps internet, with cable would be about 150 a month, or 50 each. Now all that to say, I literally know next to nothing about networks and would like to try and figure out the best solution for me. The way the network is setup, is the main router or moden, whatever it's called, is in the car lots office, then a cord is ran to the back of my apartment into another router which I'm assuming is just acting as an extender. But then by the time the signal gets to the living room which we have our 3 computer setup, the signal is kinda crummy so a while ago I bought an Netgear AC1900 extender hoping that would help the signal, and so all three computers can be wired into the extender. By the way, the netgear nighthawk extender in the living room, is extending the back hallways router extender. Tried extending the main signal from the host box but the strength isnt good enough to extend that. And I just don't know what to do, or try to do to get the most out of it all.
One thing to note, is there's a cord running from the main box, and into the back hallways router, does that matter? If that matters, should I also run a cord across building from main modem into the nighthawk extender, then have the three computers wired off of that? Or just run a cord from main modem into just the main computers ethernet, which is mine?
I'm sorry if this is incoherent junk, but I literally know nothing about networks.

 

[failboat]

Below is the most basic setup. There needs to be a router at the starting point and you will be on the same subnet as everyone else. This will get your speeds up if you don't care about separate networks. You can nest your routers but it requires more troubleshooting and it won't really separate your traffic from the others, anyone with access to the primary router can analyze packets. You need multiple IPs from the ISP or someone to configure VLANs on a device you only have admin on, if you really want separate networks.

ISP modem/router----cable to apartment----> switch (plug into LAN port of a router and it's a switch) -> nighthawk (configured as Wireless Access Point WAP)

If you can plug a cable into the nighthawk you don't want to extend the wifi. This is a last resort and doesn't have great performance. If a bad signal goes in a bad one comes out. I didn't look up if it has a WAP mode but that's pretty standard.