What Willie said. The captain usually delegates that responisbility to the officer of the deck (OOD). As soon as the Captain steps on the bridge, the first person who spots him or her (usually the junior OOD (JOOD) an enlisted person) announces "Captain's on the bridge". At that point the OOD and others on the bridge will give the CO a complete briefing on the ships condition, course, heading, and other vessels in the area. The captain will either take the con or let it remain in the OOD's hands. If it's a nice day, the Captain will go on the starboard bridge wing and sit in his/her chair. If not, the captain will sit in his/her chair just inside the starboard bridge wing door. NOBODY else sits in those chairs.