As each of your posts reaches the pay out day (7 days after its creation), you will be rewarded with steem + steem dollars + steem power. The amount will depend on the amount of the post.
After you visit your wallet section, you will see how much you have been rewarded and all you need to do is click on the button 'Redeem rewards / Transfer to balance'

Every time the steem + steem power + steem dollars (sbd) will be accummulated into your wallet. You can then buy steem with your steem dollars and either exchange them with cryptocurrency or power up to increase in steem power.

I hope that I understood your question, please let me know if there is something else you would like to know.