first you must be loged as ROOT using PUTTY
A) upload patch via FTP from https://www.magentocommerce.com/products/downloads/magento/ … NOTE: you must select correct magento version
B) using cd.. navigate to magento root folder
D) run sh patch name.sh
if this is not working try first: yum install patch … this will download and update all tools
after this run again sh patch name.sh