I am new with bitcoin , and i want to start investing in it to start earning gain.
my Q? i dont know how to start and where i should begin my first steps, waiting your ideas

Nice though that you've decided to invest in the new internet gold. Since you're new I'd recommend that you read a lot of articles about cryptos and bitcoin investment. Apart from that too you should also go learn about trading (I mean forex trading) as it can make you more mony in the long run if you are good at it.. Though it takes time to say you're now a good trader