Update description of anomaly monitor alert conditions (#306)

Co-authored-by: Mano Toth <tothmano@gmail.com>

Author: benenharrington

monitor-data/anomaly-monitors.mdx

@@ -25,8 +25,9 @@ To create an anomaly monitor, follow these steps:
     - Toggle **Require seasonality** to compare the results to seasonal patterns in your data. For example, your query produces a time series that increases at the same time each morning. Without accounting for seasonality, the monitor compares to recent results only. By toggling **Require seasonality**, the monitor compares the results to the same time of the previous day or week and only triggers if the results deviate from the expected seasonal pattern.
 1. Click **Add notifier**, and then select the notifiers that define how you want to receive notifications for this monitor. For more information, see [Notifiers](#notifiers).
 1. To define your query, use one of the following options:
-    - To use the visual query builder, click **Simple query builder**. Click **Visualize** to select an aggregation method, and then click **Run query** to preview the results in a chart. The monitor enters the alert state if any points on the chart deviate from the expected value. Optionally, use filters to specify which events to aggregate, and group by fields to split the aggregation across the values of these fields.
-    - To use Axiom Processing Language (APL), click **Advanced query language**. Write a query where the final clause uses the `summarize` operator, and then click **Run query** to preview the results. For more information, see [Introduction to APL](/apl/introduction). If your query returns a chart, the monitor enters the alert state if any points on the chart deviate from the expected value. If your query returns a table, the monitor enters the alert state if any numeric values in the table deviate from the expected value. If your query uses the `bin_auto` function, Axiom displays a warning. To ensure that the monitor preview gives an accurate picture of future performance, use `bin` rather than `bin_auto`.
+    - To use the visual query builder, click **Simple query builder**. Click **Visualize** to select an aggregation method, and then click **Run query** to preview the results. 
+    - To use Axiom Processing Language (APL), click **Advanced query language**. Write a query where the final clause uses the `summarize` operator and bins the results by `_time`, and then click **Run query** to preview the results. For more information, see [Introduction to APL](/apl/introduction). 
+    In the preview, the boundary where the monitor triggers is displayed as a dashed line. Where there isn’t enough data to compute a boundary, the chart is grayed out. If the monitor preview shows that it alerts when you don’t want it to, try increasing the tolerance. Inversely, try decreasing the tolerance if the monitor preview shows that it doesn’t alert when you want it to.
 1. Click **Create**.
 
 You have created an anomaly monitor. Axiom alerts you when the results from your query are too high or too low compared to what’s expected based on the event history.