Open up one of your customers and you will see there is a New Order button to click on to create an order for that customer.

One the product(s) are added you can edit quantities and unit prices on the order before creating it

Open up any order that you want to copy. Click on the dropdown arrow next to Edit Order and you will see the option to Duplicate Order

Similarly to the New Order button an order template will be created with all the items from the order you duplicated.

You can then change delivery dates, add/remove products and change pricing or quantity before creating the order.