It says it is locked with a passcode so I cannot restore it

You need to unlock the iPad before you connect it to iTunes. Have you done that? If you have, and the problem is that you've forgotten your passcode, what happened when you followed the steps mentioned in the article that you came from: that is, to put the iPad into Recovery Mode?

The steps are very specific and you have to follow them exactly. If you have tried those steps and something did not work as expected, please let us know which step didn't work (in a way that we can identify).

Note that different iPad models have different procedures for putting the device into Recovery Mode. Again, you need to be precise and use the steps for your particular type of iPad; that is, an iPad with a Home Button or an iPad without a Home Button.