Adding products quantity to price = a subtotal

Unable to figure out the conditions for product quantity + price = subtotal then moving to the next product option. Finally a total.

How do I set up the conditions?

I think you were looking for the sub products feature of the Product List field. Please check the user guide : Create Sub-Products Based on a Product Option

When sub products is enabled, there is option to show the sub total of each item selected as well as a grand total at the end.

I hope this help. Let us know if you need further assistance.