The first chapter introduces you to the core narrative and initial gameplay mechanics. You'll be tasked with investigating a mysterious military presence in Costa Rica. Focus on understanding the stealth mechanics and utilizing your binoculars to mark enemies. This chapter is relatively straightforward, designed to ease you into the game's flow.
Don't be afraid to experiment with different approaches. If you get caught, try to adapt your strategy or use the environment to your advantage. The early missions are a great opportunity to practice your CQC and tranquilizer gun skills, which will be invaluable later on.