Any command I put into the LXTerminal of my raspberry pi, it says Sudo unable to resolve host (none) I can’t download anything, even Sudo apt-get update How do I fix this"?
Have a look at
There you should find one line with the name of your machine.
Then have a look at
There you should find two lines. One localhost and one with your hostname:
127.0.0.1 localhost 127.0.1.1 your_host_name