To add a link to a button, click on the button. When you have selected the button, you will see a “Url” field in the right column, where you can type the link URL.
This is how you can do it in the old version of Chamaileon editor:
This is how you can do it in the new version of Chamaileon editor:
If you are not using Chamaileon yet, you can register here for free and add a link to a button easily.