Hi Have a look at this how to guide.
The above article covers only commands when you are already in a mysql session.
To start a mysql session you could issue a command like this in the linux terminal:
mysql -u root -p
“You can access the MySQL CLI using the mysql command followed by the -u option for the username and -p, which tells MySQL to prompt for a password.”
You might want to have a look at this other MySql HowTo.