In Replenishment Settings, you can review some of the underlying data, assumptions, and settings on which the Replenishment Recommendations are based.
While some settings are global, the data is always SKU specific, and you need to drill down to one of the SKU's first:
Vendor: Where this SKU is ordered from.
Locations: At how many locations this SKU is stocked.
Total Stock Held: How many units are currently on hand in our stock.
Total on Order: How many units have we already ordered, but not yet received.
Avg. Rate of Sale: How many units do we sell every week (p.w.) or per month (p.m.)
Current Service Level: This number deserves its own chapter:
Current Service Level
And not only that, we have a full article describing what Service Level is about, because it is a key adjustment of the prediction algorithm.
With full understanding of this setting, you can now adjust it. Here, at the global level, you will adjust it for all location. The range of adjustment goes from 50% to 99%, but it is rare in practice to use a value larger than 95% or smaller than 80%.