For this easy tutorial you will need to have administrator access to the server its self .
1. Login to the server eather by SSH or locally on the host.
2. Change the directory to etc/php/apache2
3. Open the file php.ini
4. Change the valve on the line contaning post_max_size =
5. Close and save the php.ini file
6. Now your Server runing Sentora should allow you to upload larger files up to the size you have now allowed.