Use a QR Code Scanner
QR or Quick Response codes are a quick and easy way to get your device to a specific place on the web such as a map, document, video or website.
QR codes are used almost everywhere, for hundreds of different purposes.
Amazingly iOS does not have a native scanner built in so your teacher will have to install one from the app store. A free one is perfectly fine and there are hundreds to choose from. Qrafter is as good an option as any and one I can recommend for students and teachers.
To USE a QR code all you need to do is load your QR reader app (Just type 'QR' into your spotlight search if you are unsure of what the app might be.) and hold the iPad camera up to the QR code you are scanning. From there it is very plain sailing and you just follow the instructions on the iPad which should take you to your link.