In addition to what @blocktrades said, once rewards start, you will also earn additional steem power, so you don't necessarily need to buy more to get to 10x, you can earn them on-site too.
Payouts for writing and upvoting posts are paid in another currency called STEEM-backed dollars which you will be able to sell whenever you want and you don't have to buy anything to earn them. These payouts are scheduled to being on July 4th for all the posts you make before then. The easiest way to make money on STEEM is to post some popular content, especially if it's original content, and let others upvote it. The first payouts could easily be the highest payouts, so you've joined at a great time.
Go there https://steemit.com/@andzzz and press "power down"... they will all released week after week (104 weeks total) I don't advice you to do it!!! You can earn much profits just posting, commenting and upvoting others!!! On 4 July you will get real steem backed dollars plus much more vested STEEMs. Read the white paper if you want here https://steemit.com/steem/@liondani/steem-whitepaper-download and get familiar with steem backed dollars here https://steemit.com/steem/@dantheman/introduction-to-steem-dollars-sbd
There are "steem", "steem power" and "steem dollar" in the wallet page. what's the difference?
Steem power is vesting steem. Steem dollars is pegged to a dollars worth of steem.
You cannot withdraw without first depositing 10x. Once you did that, you need to 'power down' as mentioned by liondani.
so actually whatever i earn i cannot get out if i wont buy extra coins yes?
In addition to what @blocktrades said, once rewards start, you will also earn additional steem power, so you don't necessarily need to buy more to get to 10x, you can earn them on-site too.
Payouts for writing and upvoting posts are paid in another currency called STEEM-backed dollars which you will be able to sell whenever you want and you don't have to buy anything to earn them. These payouts are scheduled to being on July 4th for all the posts you make before then. The easiest way to make money on STEEM is to post some popular content, especially if it's original content, and let others upvote it. The first payouts could easily be the highest payouts, so you've joined at a great time.
And a reminder: after 4 July you will get steem Dollars every 24 hours