Rule building in MS Teams uses the same concepts as in Slack and this is covered in greater details here: Creating Monitoring Rules
In summary, there are 3 types of rules:
Threshold - A threshold rule allows you to set a specific value for any KPI.
Example: Alert me if my weekly spend ever drops below $2,000
Fluctuation - A fluctuation rule allows you to set a percent change for any KPI.
Example: Alert me if my weekly spend ever changes by more than +/- 30%
Anomaly - Trigger any time the 7-day moving average deviates from the 28-day moving average. These alerts are set up automatically and do not need to be created.
Rules can be configured in one of three ways:
@eletype rule
@eletype settings ➡️ then click on the Rules button
Or click on the ⚙️ icon in any notification
Here is what rule building looks like:

You can Enable, Pause or Delete a rule by clicking on the Status dropdown, like this:

Note: All new connections will automatically have a 10% spend fluctuation rule.