Trading in shares is very easy with online facility, Register with any SEBI approved broker to get demat and trading account once your account opened successfully you can buy shares and sell shares,how to do this will be trained by broker,
If you want to open demat adn trading account to trade shares you may prefer open account with ventura securities who charge less brokerage, 0.01% on intraday and 0.10% on delivery,
Contact me at ganeshbabu.tax@gmail.com if you need help on opening account