Our software update is now concluded. You will need to reset your password to log in. In order to do this, you will have to click "Log in" in the top right corner and then "Forgot your password?".
Welcome to PokéCommunity! Register now and join one of the best fan communities on the 'net to talk Pokémon and more! We are not affiliated with The Pokémon Company or Nintendo.
You double click the .jar file.
Keep in mind that since it's a Java application, you need to install something like OpenJDK and make sure to open the .jar file using OpenJDK's "javaw.exe".
EDIT: Also, keep in mind that this hasn't been updated in over 3 years and it may not work with Pret's Pokeemerald.
It will absolutely not work with the Pokeemerald-expansion due to changes in how it processes trainer data.