From within I.D.A. click on "Plugin Manager".
Click on "Get Plugins"
Check off the plugins you wish to try.
When the "Registration screen" pops up, click on "Try", then on the next pop up screen click on "Don't register" your trial will then begin for your plugin(s).
Please note: Everytime I.D.A. is restarted you will need to complete this process. Once the 15 day trial period is over, the leads for the plugin(s) will no longer populate into I.D.A. until the plugin is actually purchased and full registered.