ETF is an Exchange Traded fund and is available on the trading platform for you to buy and sell. Add it to the marketwatch like you would add any other equity stock and you’d be able to buy/sell.
Here’s the list of various ETF’s with symbols trading on the Exchange:
List of Equity ETF’s: http://www.nseindia.com/products/content/equities/etfs/equity.htm
List of Gold ETF’s: http://www.nseindia.com/products/content/equities/etfs/gold.htm
List of World Indices ETF’s: http://www.nseindia.com/products/content/equities/etfs/world_indices.htm
List of Debt Indices ETF’s: http://www.nseindia.com/products/content/equities/etfs/liquid.htm