Once you have decided which bag and how many you want, all you need to do is click on the orange add to basket button on the far right of the table on the product page.

The image below illustrates this. Click on the image to enlarge:

You’ll then see an overlay screen giving you the option of upgrading your order with a bulk buy (which works out cheaper per item), to continue shopping or to go to checkout. Choose your option and carry on.

The image below illustrates this. Click on the image to enlarge: