[TYPO3-english] Major Site update process

[Adrian Manning]

I do not know if this is the right place to ask this question.

Where can I find information about how to make a major update to my site?
My problem is the site runs on a shared host, so I only have access via FTP and phpMyAdmin.

I want to make a copy of the current site (database and typo3 code) and redirect any users to this copy while I work on the original. I need access to the modified original to test it. Finally I need to switch back to the updated site when everything is working correctly.

I need an easy to follow guide that does not require admin rights.

I feel this must be something hundreds of people are doing, but have not been able to find the correct guide yet.