To connect to the mysql client program:
mysql -u root -p
If you did not set a root password, just hit return. If you did, then enter your password.
Now use the grant command in mysql to set up a user to access mysql.
You can set the root password using grant, or more easily using
mysqladmin as follows:
mysqladmin -u root password MyNewPassword
NOTE: password in this is a command, MyNewPassword is what you want for your new password or you could use the SET Password SQL command.