First you have to activate the plugin in the config.txt, then you enter a game and press start+select, the if you want to unlock all at once, press L+R, or if you want to unlock just one, press L+start and Use L+UP / L+DOWN to select the trophy ID.I have installed like it says but just can’t get the menu to open up
All the discussions on the topic, which I see on the Internet end up with the discussion on the merits of taking trophies or not. Basically nobody should comment on the ethical part or not, because everyone does what they want. But no one answers what we really want to know. Whether it is safe or not to use.
Seeing how the plugin is only a day old, there's no way to know.
But since it's for trophies, you should never sync any hacked trophies you make to PSN, as this will more than likely get your account banned. If you, for some reason, absolutely have to sync trophies, use a separate account from your main.