How to rename hostname and username in debian 7

See you again with me, in this opportunity I wanna explain to you about rename hostname and username in debian 7. I have this problem when I follow WSC or in bali with name LKS ( Lomba Keterampilan Siswa ). Much problem that i have but i have to fight to be a winner. Below is some steps that you can try if you have same problem with me. So, lets do it.

first step we rename the hostname
this is the first hostname before you rename

now you log in with username and password that you have write before
after you log in set your hostname on hosts with command #nano /etc/hosts
in here change your hostname become hostname that you like

and then you write again your hostname with command #nano /etc/hostname
change your hostname become hostname that you write in hosts before

now reboot your server
and then look the change

steps two is rename username
after you log in with username before now you back again to directory home with command #cd /home
for look the username that there you can use command ls
and you can see the username

now write the new username

and then the password of username

if you to check you can use command exit until page where you first time log in
maybe thats all for today see you again bye