Links inside the IEHIAS:

Just write (e.g.) [ node:335 ] (without the blanks) - and a link to a page will be shown like this: Tutorial: How to insert hyperlinks

The number of the page is shown above the page title.

Hyperlink:

The left icon can be used to create a hyperlink.

If you want to have a descriptive text as a link, the first step is to highlight  the text. If you are happy with just the URL, you may proceed by just clicking the icon. The popup will show you different options:

1.) Link Type:

• URL: Use this option to link to sites other than the one you're editing
• Link to anchor in the text: Links to an anchor in the current node.
• Mail: Choosing this option creates a mailto-Link

2.) Protocol:

To create a hyperlink to another website, choose "http://".