An extension was created for Thunderbird for instance which can be installed just like any other extension available which means that you have to download the file, open Thunderbird, go to Tools > Add-ons and select the file after clicking on install. Outlook users can download an add-on for Outlook.

The developer suggest to disable the default spam filter in both programs if you want to stick with Spamato. You can do that in the Account options in Thunderbird by disabling all options under Junk controls. Spamato is doing a good job from what I can tell. I have been using the extension for Thunderbird for just one day so it might be a bit early to judge it correctly but it looks to handle spam superbly.

Spamato creates a folder of the same name when it is installed where all detected spam is moved into. Oh, you do need Java to be able to run Spamato. Sometimes you will have to located the Java executable by yourself and add it manually to the options of the extension.

Everything is well explained and it should not be a problem to locate the javaw.exe file.