You can find the registration steps in this post. In short, download the app from Play Store (link is given above already) and register your account. After that, you'll have to verify your account. Here's how:

If your STEEM account reputation is less than < 60

Please take your picture while holding the piece of paper/board (not anything special, just a blank paper). Write your STEEM username and game tracking name on that piece of paper or board. Your face, STEEM username and your game tracking name must be clearly visible. Write a post on STEEM blockchain and upload your taken picture (the one which meets the above requirements) in your post. Make sure to use "super8ballclub" tag when posting on steemit.

See the picture for an example. (It can be a piece of paper but you must be holding it in your hands).

If your STEEM account reputation is more than > 60

Please write a post on STEEM blockchain with your game tracking name. Make sure to use "super8ballclub" tag when posting on steemit.

Once done, please wait for 24-72 hours and we will enable your account as soon as we verify your identity.