Q:Can I earn money on Steemit? How?

I think this needs a more detailed answer:

You can earn rewards via different ways on steem
a) as a blogger: you write post and comments on other post, people can upvote your content and the more people that vote for you the more rewards you receive, there is a set amount of value that will be distributed over time and the votes determine which content create receive how much.

B) as a curator you get rewards for voting. The earlier and the more successful a post is that you vote on the higher your curation reward will be.

c) as an investor you you can power up steem, that way you money is vested in the blockchain and ceases to be liquid, but you get rewarded with a high interest and voting power for witnesses. Your votes also get more weight and you receive higher curation reward.

E: as a saver, you can hold SBD, which yield interest (currently 10%) and are pegged to the USD to have stable value.