I'm trying to SSH using Putty but it's asking me for the host name. I named my "System Name" MBR and found my (local) IP address, but the following command doesn't work: ssh [email protected]
You don't have to type a command in PuTTY to connect, you just fill in a single input field, where you enter the IP address of the device you want to connect to, then press the Open button below.

If the SSH server is really working, it will first pop up the fingerprint confirmation warning, and after accepting it, it will ask for the username, where you just type root. If you haven't changed the password, the default password will be libreelec. And that's it. If anything doesn't work, then SSH server doesn't enabled, or the IP address is wrong, etc.
I'd be happy if we didn't make this an offtopic, these should be basic things for a unix system. If these things are not clear, then please let's not discuss them in this topic. These are completely general things, they have their own place on the forum here: General Support.