WordPress.org

How does Link Shortcut work?

The Link Shortcut plugin attaches itself to various core Wordpress methods and waits for a request to be made for a shortcut URL saved to the database. When one is, it simply does a redirect to the saved URL. The redirect type can be changed (301 or 302) inside the options panel.

I installed the plugin but it doesn't work.

You must have non-ugly permalink settings. If there are variables in your URLs, you'll have to use Wordpress admin to change that.

Does Link Shortcut use the Wordpress database?

Yes. Upon activation, Link Shortcut creates a table and stores all links in that table, so your existing structure does not change. If you decide to deactivate the plugin, it removes this table but creates a backup table for your convenience.