Do you have a mysql database? if not then here we go.
Before installing Mysql, make sure your repositories are up to date:
apt-get update
Now you need Apache:
apt-get install apache2
To install Mysql, enter terminal or screen and type in these commands:
apt-get install mysql-server
Follow the instructions.
If you miss the chance to set the password then you can always do it within the mysql shell.
Run the mysql setup script:
mysql_secure_installation
The prompt will ask you for your current root password. Type it in.
Once again follow the instructions and remember pressing N is for No and Y for yes.
INSTALLING PHP? not sure if it's necessary but here we go:
apt-get install php5 php-pear php5-suhosin php5-mysql
Answer YES twice and it will install itself.
Finish up by restarting apache:
service apache2 restart