Api to add customer and details

So I am using zapier to interrogate a spreadsheet that has someone inputting orders

So if customer
MR Smith orders
2 x socks
2 x t-shirt
1 x jeans

I need to add the customer information to be added to the customer dataset and then a list of products added to the order dataset on separate lines and the customer I’d assigned to them

Can anyone help? I am quite a newbie at this so a simple explanation or a walkthrough would really help.