A simple search around here or even a Google search would do the trick but anyway, here is the tutorial on how to install Plesk on CentOS.

1. Remove Exisiting Versions of Apache, PHP, MySQL and Cyrus

These compents can and will cause conflits with the Plesk install so your best of removing them run the following:
Code: 
[root@centserver ~]# yum remove http* 
[root@centserver ~]# yum remove php* 
[root@centserver ~]# yum remove cyrus* 
[root@centserver ~]# yum remove mysql*
2. Disable SELinux status

SELinux or Security-Enhanced Linux will also cause conflits with the plesk install and when you are adding / creating websites, your best to disbale it.
[root@centserver ~]# setenforce 0

3. Make a working directory

Make and navigate to your working directory where you will run the auto installer
[root@centserver ~]# mkdir /root/plesk
[root@centserver ~]# cd /root/plesk

4. Get the plesk auto installer

Register and get the file location from Then type:
Code: 
[root@centserver plesk]# wget http://plesk_auto_installer_url
5. Chmod it

To give it execution permissions
[root@centserver plesk]# chmod +x plesk_auto_installer_filename

6. Run the auto installer

[root@centserver plesk]# ./plesk_auto_installer_filename

7. Select the Product you want to install

Normally the highest verion there is what you want to install

8. What options to install

I would suggest just installing
1, 2, 3, 4, 5, 6, 8, 9, 10, 15, 16, 18 and 19
but install what ever packages you think you will need / use

9. Continue the install

Pick N to continue the install then when its finished jump into a web browser and goto https://ip-address:8443/

10. Follow the on screen instructions and done :-)