Go to the page you want to link to. Right-click in the address bar. Select copy. Go to your AnswerBank answer. Right-click and select paste.
Alternatively, you can just type out the URL. Remember, though, that if you want it to be 'clickable', it has to be the 'full' URL. e.g. www.google.co.uk isn't clickable but http://www.google.co.uk is.