Your journey begins on the surface of SR388. This initial area serves as a tutorial, introducing you to basic enemies and environmental hazards. Your first goal is to descend into the planet's interior.
From your landing site, head right until you encounter a large shaft. Descend this shaft, being mindful of the flying creatures. Continue downwards, exploring any side passages for potential Missile Expansions or Energy Tanks. The path is relatively linear at first, guiding you deeper into the planet. You'll soon encounter your first Metroid larva.