Sorry for asking this like some kind of dumbass, but I just bought the game, but dont know how to launch either of he dlc's.
So do I have to beat the game first? I was planning on doing that anyway, but I'd like to know how to play it.

Again. sorry to ask. Just kinda worried

You don't need to unlock anything, both expansions have independent binaries.

There should be shortcuts to both expansions somewhere. Anyway, the main game executable is in the installation directory, but the expansions executables are inside the folders FEARXP (Extration Point) and FEARXP2 (Perseus Mandate). fearxp.exe for Extraction Point and fearxp2.exe for Perseus Mandate (the other executables are for configuration and multiplayer propourses).

In case you are using the Galaxy client you can launch the expansions from the submenu More > Others