Total Beginner

Hi, I am very new to this, so please bare with me.

I have an existing website and I wish to update some of the pages.

Firstly how do I determine which page is which?

I have accessed the site via FTP, but I am unsure as to how to open up the site content. I don't want to delete anything by mistake.

Once I have worked out how to do this, I will then need to know how to upload the new information.

Can I just amend each page, or do i have to create a new one?

Thanks in advance.[left][/left]