Steps are the conditionals of an achievement to be considered complete. They are present just on achievements that are configured to be earned by completing steps.
Lets see an example to see how it works:
On first example we are defining a step for users who log in 2 times limited to 1 per week and on second step we are defining that users need to comment on “Sample Page” 3 times without any time period restriction.
If the achievement has checked the option “Sequential Steps” then users comments on “Sample Page” will not take effect until they complete the first step.
There are just a few examples about how to set up steps. Of course, GamiPress includes more ways to award your users like commenting on a specific post or by completing other achievements. You can check the full list of built-in events here.
If you want to meet deeply how to setup achievement steps check this guide.