Yes, you have to create your ONE account in the iOS app, please download the app through this link: http://app.onechain.one/appstart_en.html  with invitation code: 444905.

Regarding the rewards for blogging articles, please refer to the general rules: Media Bounty 20% - 40 000 Tokens, we will determine how many tokens you will get at the end of campaign based on the number of articles and the quality of each articles.