I have a dumb TV which doesn't play most of the video formats like mkv or mp4. I want to make a system using Raspberry pi so that i can not only connect my pen drive or external hard drive using usb port but also make my tv smart by being able to use apps like youtube, chrome, etc on my TV using Wifi. Also i want to be able to access files or play videos from a pen drive connected to my WiFi Router using USB port on router using Wifi. and Is it possible to do screen mirroring or accessing files or videos from my android phone using wifi on Rasberry Pi. If all this can be done can you please guide me I am doing engineering in electronics and am new to Raspberry Pi. I would like to make this my first DIY project on Raspberry Pi. Please help
Just take a look at some of the many Media Server installations available for the rPi such as Kodi (formerly XMBC) or OpenElec. They give you all your video playing needs. For Android screen mirroring you would need to look for an Android app that does this - this video shows how this is achieved using the YouMap app.
BUT - to be honest, it doesn't make much sense to go through the route of installing one of these distributions when you can do all that you want to do with a Chromecast dongle, which incidentally costs the same as an rPi and works out of the box.