This is the identifier you use to refer the achievement within your code
With this id, you can refer the leaderboard irrespective of the platform you are on.
This is the identifier which is specific to a platform. Usually these are the id's you see in iTunes Connect -> Game Center and Google Play Game Services dashboards.
If the platform id is not same among all platforms, you can set id per platform. Just enter the specific id under the listed platform.
Title for this achievement
Number of Steps to Unlock
If the achievement is an incremental achievement (an achievement which needs steps to complete it), you need specify the number of steps it takes to finish this achievement. For one-shot achievements, this value should be 1.