100mb automatic automatically cart demo downloaable feature form goods information matters online order page pictures processed products selling shopping

I am new to the online shopping cart feature. Now what does it mean by the 100MB is that for pictures of the products. Also, how does the person's order get processed once they put their information into the form. Does it do it automatically.

That 100MB matters to you only if you are selling downloaable goods. To see how an order gets processed, please see our demo page. It's all automatic.