I am new to trading. I don't have an experience and reputation about trading and that's why I'm here for asking a help to an experienced person.
Can you give me an idea on how to trade and where to trade?
for the place to trade it depends on what you want to trade, for bitcoin/usd there are bitfinex, bitstam, kraken and btc-e where you can start trading with fiat.
for trading bitcoin/altcoin you can choose poloniex, bittrex or c-cex.
choosing which one depends on where you live and after you read their rules (TOS) and fees and possibly their methods of deposit and withdrawal for fiat.
about how to trade I have to say you should start with a small amount or no amount and just play with a excel spreadsheet for a while to learn how you can make any profit then invest small amount and grow it over time.