Why is the Internet not working through the Ethernet cable?

Question

Computer networks

Everything is simple, there is a PC, there is a router, a telephone cable, an adapter and another telephone cable.
Bundle Cable BASIC - the router works so-so , but it works.
Bundle Main cable - adapter - ADDITIONAL cable - the PC does not work at all, the PC does not see that the cable is connected to it, therefore there is no Internet, but this, in my opinion , is not correct, how can I fix this?
Bundle MAIN cable - router - ADDITIONAL cable - the PC works halfway, the PC sees that a wire is connected to it and SOMETHING is going through this wire, but it cannot recognize the network, therefore the Internet without access to the network . How can this be fixed?

Why do I need an adapter and an additional cable?!

An adapter and an ADDITIONAL Cable are needed in order to increase the range of the MAIN Cable , since it, in turn, is short and does not reach the PC.

Well, just in case

WHAT TO GOOGLE?

Can't find it on google

Answer 1

1. Mismatched adapter
2. Crimped wires in one of the cables
3. Mismatched pairs in the cables

Answer 2

telephone cable? ethernet? What an odd mix you've got.
And what router, if not a secret?

Answer 3

I agree with CityCat4, but cable length also matters. The length cannot be more than 100 meters without active equipment (repeaters, hubs, routers, etc.)