Excel Newbie Needs Help!

Hey everyone, I'm fairly new to making complex spreadsheets in excel, and I'm trying to do something way out of my league! I have an order form where I track individual orders and then add them all up at the end of the day to track total purchase of each product. Right now I'm counting everything by hand, but I'm wondering if there is a way to make it automated. I've figured out how to make a drop-down list, and wanted to be able to choose a product from the list and put the quantity in the next column over. Then, I would like to add up all the orders for each specific product. Is this possible? I'm not sure I've explained myself clearly, so let me know if you need clarification. I've attached a sample of the order form as it is now (but I'm definitely willing to change the layout if that will make formulas work more smoothly!) Thanks everyone!