This tutorial explains how to install ImageJ and the AMPT plugin.
Download and unpack Fiji using the distribution appropriate for your platform from the Fiji Download site.
Note that these instructions are a specific instance of the more generalized Following an Update Site instructions from ImageJ.
Start the Updater.
Start the ImageJ Updater (Help > Update...)
Add a new update site
Click on the Manage update sites button to bring up the site management dialoag.
If AMPT is not already in the list of update sites, add AMPT as a new update site.
Ensure that the checkbox on the left (in the Active column, though the column header may not be visible) is checked.
Close the dialog.
At this point, the ImageJ Updater will show an option to install the AMPT plugin and its dependencies. Apply the changes.
Once the plugin has been installed, ImageJ must be restarted. Upon restart, the AMPT plugin will be available from the Plugins menu.