Well first steem is a token, not a currency. Mining involved currencies like Bitcoin, Ethereum, Litecoin, etc. There is 2 way to mine, using your own computers or via cloud mining.

Both way require a large investment. If you chose to build your own mining rig, you'll have to buy everything and the cost of running these rigs can make your electricity bill explode.

Cloud mining on the other hands is easier. No material or electricity cost. You buy a contract for the hash power you want and the company will do the rest, mine for you.

For steemit i'm pretty new also but from what i can see if you want to make serious money you need to build yourself a good following. This is accomplished by posting quality stuff daily.

Good luck