We will need:
Router with a free LAN connector (it is yellow). Network cable. A small cable is included with the router. But, if you need a longer cable, then you can make it yourself. How to do this, I wrote in the article How to make (compress) a crossover. Or just go to the computer store and ask them to squeeze the network cable of the length you need. A computer with a network card (usually it is integrated into the motherboard). Well, or a laptop, a netbook with an RJ-45 network connector.
We take our network cable, it looks like this (you may have a slightly different one, I will enter a different length):
We connect one end of the cable to the yellow connector (LAN) of our router.
It doesn’t matter which of the four connectors you connect the cable to.
Now we connect the other end of the cable to our computer, or laptop.
This is what the network connector looks like on a computer:
After connecting the network cable, one of the four indicators that indicate the connection to the LAN connector should be lit on the router.
Now we look at the computer screen. If on the notification panel (bottom, right) you see this connection status (as in the screenshot below), then everything is fine. Internet is already working.