The Prolost After Effects presets should be copied to your User Presets folder. The location of this folder varies with your operating system and your After Effects version.

Mac

~/Documents/Adobe/After Effects <year>/User Presets/

Replace <year> with the CC version you have installed, e.g. After Effects 2025.

Windows

My Documents\Adobe\After Effects <year>\User Presets\

Replace <year> with the CC version you have installed, e.g. After Effects 2025.