1. Start with setting one up on you local desktop first so you can become familialr with it.
2. Buy the book - it's an valuable tool and how I first learned to do ZenCart:
http://www.zen-cart.com/index.php?main_page=page&id=16
The book also helps explain to set up the database on your local.
3. Once database set up - download 1.3.9h (or the lastest) via the home page:
http://www.zen-cart.com/index.php
4. Install your cart via the book guidelines or if still confused - follow this post:
http://www.zen-cart.com/forum/showthread.php?t=161795
5. Read the security recommendations - definitely needed for you LIVE shop:
http://www.zen-cart.com/wiki/index.php/Important_Site_Security_Recommendations
6. Make a backup of your store on you local - make a new folder - call it "ZenCart-Base Backup" copy all zencart files into it. You now have the original files stores away so if you screw up making your changes you can reload an original file over he file you screwed up.
7. Customise your site using templates - more info here but you don't need to worry about understanding it right away - just keep it in mind:
http://www.zen-cart.com/forum/showthread.php?t=132818
http://www.zen-cart.com/forum/showthread.php?t=132818
8. For setting up the look of your shop - read this but don't worry about the fire bug thing at least not right away - it helps explian the css - this control colors, fonts, background etc.:
http://www.zen-cart.com/forum/showthread.php?t=135954
7. For header image size issues:
http://www.zen-cart.com/forum/showthread.php?t=130792
8. How to get rid "Congratulations! You have successfully installed Zen Cart E-commerce Solution"
http://www.zen-cart.com/forum/showthread.php?t=176481&highlight=Congratulations%21+successfully+installed
9. How do I change the "Sales Message Goes Here" or "Tagline Here" text?
https://www.zen-cart.com/tutorials/index.php?article=127
10. Now once you get going - and by now you'll feel a little better about doing this on your own - start playing with the catelogue and by this I mean - making products, categories, setting up the prices, deleting items etc.
11. If you only have a small number of items do it manually - category / products etc but before you do - since it appears that you're in the UK - think about your shipping options: FedX, UPS, Royal mail
12. If you have a lot of items use Easy Populate - you can find info and download info here:
http://www.zen-cart.com/wiki/index.php/Easy_Populate
then install it onto your Zencart.
13. I had some duplication issues with Easy - my user error - this post has a really good tip in using it:
http://www.zen-cart.com/forum/showthread.php?t=175392
14. Once you have done all of the above you and are comfortable - you are ready to go live - repeat all of the above to your live server - see my other post in this thread to help you out.
Don't worry it's easier than it sounds :thumbsup: