@detlev @elizacheng @infobunny - look who is here :-)!
@zoolander - you should read the FAQ first (https://steemit.com/faq.html) - here is a site with all apps built on the Steem blockchain you can use: https://steemprojects.com - as @steevc pointed out engage with others, create content about topics you like, ideally format them visually appealing and be patient.
Very important is to keep all your keys in a safe place and never ever use your master password anywhere. Re mobile apps on Android there are some, I personally used esteem usually but maybe do a post and ask the community this question.
Here is the link to the app on Google Playstore: https://play.google.com/store/apps/details?