1. Type out the text you want to add the link to, e.g.:
Theaker's Quarterly is the king of magazines!
2. Highlight it and click the insert hyperlink icon (the little world), to get this (albeit with square brackets):
(url)Theaker's Quarterly is the king of magazines!(/url)
3. Add = and the link to the first url, e.g.:
(url=http://www.theakersquarterly.blogspot.co.uk)Theaker's Quarterly is the king of magazines!(/url)
The round brackets are just so that you can see the example - with square brackets that becomes:
Theaker's Quarterly is the king of magazines!