Using the regular editor on the “Add New Post” page, highlight the text that you wish to turn into a link, and then click on the link button in the formatting bar:

A new window will now pop up, with various entry fields:

First, paste in the link you want to use in the “Link URL” field. All the other options can be left unchanged – just click “Insert”.
However, if you want then you can use the other options as well.
The “Target” drop-down menu allows you to determine whether the link will open in the same window that your reader is currently reading your article in – and so taking your reader away from your words of wisdom – or open up a new window.
The “Title” field allows you to enter a further description of what the link is about or where it leads to that will pop up if your readers hover their mouse over the link.
The “Class” drop-down menu is best ignored.
If you decide you want to delete a link, simply highlight the text and click on the “Remove Link” button. To edit a link you’ve already inserted, just highlight the text and click on the “Insert Link” button again.
For more advanced users, you can add links manually by clicking on the “HTML” button to the top right of the text entry box, and putting in the code yourself.
