Make sure you have a recent backup of your iPad before you update!
The easiest way to update your iPad is to simply install the update "over the air". Here are instructions for how to update wirelessly. You must have 5.1 GB of space available on your iPad, or this will not work.
Here is a video tutorial which shows how to update your iPad via wireless.
To see how much space you have on your iPad, tap Settings > General > About. On this screen you can see how much storage space is available.
If you don't have 5.1 GB available, you can still update over the air if you delete some things. To see what each app is using, follow these instructions.
Please do not update wirelessly during the school day! (after school is fine)
If you can't create enough room, you will need to connect your iPad to a computer which has the latest iTunes installed. Check the "Update Your Device Using iTunes" of the previous instructions to see how to do this.
You may do this on a school computer in the library, please bring your usb sync cable or ask for one at the desk.
You can also do this at home, if you have a computer with iTunes available.