Lucy dont worry if you dont know any HTML. Choose yourself a cart that will do all you require. Try and choose one that has good free support like a online forum for users to interact. I currently use what bigpoppa is using-zencart. When you know what you want to do have a search and you will be surprised how straight forward the instructions are. Some can be confusing but all it takes is for you to post a question and wait for a reply.
I have very little HTML knowledge well its alot better now and i did do a course years ago from basic. Would you be surprised if i told you that i designed my site and only needed to use HTML a few times. The majority of carts use something known as CSS which links into the html code. The way i have understood it is that the designing of the site is done through the css and the language side through HTML. Sites also use powerful script languages such as php, javascript or pearl for more complex operations.
This may sound confusing to you at the moment and it maybe due to the way i have explained it but be assured its not as hard as it may sound. you will need to do alot of reading but it all pays off.
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