Both of the answers given by Jainimus, and Cardelean, are appropriate, but there is much more to know.
This hub might be useful. It describes exactly what an HTML link is and how it relates to some of the functions in Hubpages: http://hubpages.com/community/How-to-use-a-TRACKER...
If you want to link to multiple hubs, you can use a Link Capsule.
Also, if you write Hubs that all are somewhat related, by category for instance, then you can use the "Groups" function and at the bottom of each hub related links will automatically show up to your grouped Hubs.
I'd be happy to elaborate if you want.