You see in your Wallet how much Steam Power you have. To get more Steam Power you Need to buy or collect Steam in your Wallet and then Push the "Power Up" button. Thats the way how to get more Steam Power. When you habe much Steam Power then you have also some Limit how much Content you can "like" before your dayly/weekly have been used. On https://steemstats.com you can see how much % of Steem Power u used already. And dont worry it will regenerade after some hours if u use it