How to connect to WIFI when my laptop says "wireless network connection" doesnt have a valid IP configuration

This is because your laptop has a wireless adapter fitted to it.
Most of the time using the wi-fi is handy for moving around the house since a laptop is portable.

You can only ever have one connection per machine.
So what is happening is your wi-fi adapter is still turned on.

In order to use the wired connection you must first disable your wi-fi of the laptop via a switch on it.
Or by holding down the Fn key, then hitting the number or symbol on the numbered key at the top of the laptop keyboard that looks like the wi-fi symbol.

You can then plug the Ethernet cable into the laptop and you should be able to connect via the wired cable.

Then when you wish to use the wi-fi again simply unplug the cable.
And turn your wi-fi back on by the Fn key and the numberd or symbol key indicating it to turn it on again.