First you must log into your account (or create an account if you don't already have one). Find the "Drop this balm" and "Buy this kit" purchase buttons on the right navigation margin.
If you click on either the Drop this balm button or the Buy this kit button you will go directly to the Shopping cart page to continue your purchase.
All the information about you and about your purchase - your Balmee, why you are dropping this balm, which StoryNet is related to your purchase, and which of the StoryNet causes you support - will be collected during the Check Out process on the Check Out page. All this information makes up the story-bit for this transaction that will be added to the full StoryNet of the game you are playing.