Lazy Sound Patch Compilation vol.1

Do we install all these patches on one file

No, you would choose just one to use at a time; it will replace the instruments with whatever patch you choose, so if you choose the Romancing Saga 3 patch, it will change the instruments to that. Then, if you decide to apply the Chrono Trigger one, it will replace the instruments to that, see? So using more than one of the patches at once is futile, in other words.