How do I Set Different Prices for Different Pack Sizes

Just installed Shopperpress Responsive and can’t see a way to have different prices for different pack sizes of the same product.

I can see how to assign standard attributes such as colour, size etc all at the same price.

However I would like to have a set up whereby I offer:

Price for 1 = £8.00
Price for 5 = £35.00
Price for 10 = £60.00

Thanks for some guidance