In all honesty a load of the issues you are having are in the help files/ tutorials etc or have been asked many times before.

Zen cart is stupidly easy to get set up and working out of the box. It's pretty much easy to make minor CSS changes (colours, fonts), remove sideboxes etc

When you want to start shifting elements around the page, for example, you'll need to edit some of the PHP files. For this you really need to understand the basics of web development.

You need to have a good text editor, or even something like dreamweaver, and a good ftp client set up on your machine.
You NEED a local copy in case you mess up or the server falls over/ gets hacked and need to make back-ups regularly.