Regarding your first problem:
They are probably just bots. You should avoid bots as much as possible, you can achieve this by blocking their origin IP address. Plugins such as WordFence and iTheme security could help you with this — they are really user friendly!
About the e commerce thing:
Simply just install WooCommerce and play around with it! Things will become clear for you eventually, the way people can sign up and put products in baskets. At least that is how I learned the ropes.
