Martin, to be a Bonsai the tree needs to meet some guidlines. if you take a look at this link i post it will explain it a little. The tree or sapling you purchased is not a Bonsai , it will need many years to become one if it ever does. Not all trees trained as Bonsai will be Bonsai.some will make great "trees" but unworthy of really being called Bonsai. Many shops/outlets are only after some quick cash and they will selll this type of sapling as "bonsai" when indeed it is not. Call it wrong, whatever but that's Bussiness for you, it happens everywhere with all sorts of merchandise.
The sapling you have aquired will be great practise for you , you'll be able to start learning How to Water a tree in a bonsai container and care for it. This will see you thru until you begin to get the hang of it or buy another tree to care for.