Vanakkam everyone ! New to Chennai. Need some help.

I will be shifting to Chennai very soon for my internship. Will be staying somewhere around Navalur - Siruseri area. Even though I have a decent knowledge about this city as I visited earlier ; there are many things which can only be cleared up by the locals only. Hence needed help. 1. How good is the public transport here ? What apps need I use to navigate them? 2. What are some good places to experience the authentic local cuisine and seafood ? 3. How is the nightlife here ? Any other tips or suggestions are welcome!