Navigate to the Dashboard.   

Select the Lead Settings tile from the "Customer" tile set.

Select Notifications/Assignments from the left hand navigation men then  

 Scroll down past Automatic Lead Assignment  then click Add Custom Assignment Rule 

Name the Rule.

Select the Rule Type from the drop down menu.

Select the Rule Criteria from the drop down menu.     

Select the users to receive email notification for the lead based on that tag.

Click Save.

NOTE: When you have multiple lead assignment rules, they will be applied with the following hierarchy: Day of the week, Custom Tag, Condition, and then Manufacturer.

Users can edit or change any created rule using the icons shown. 

NOTE: If you want to change the rule name or tag you will need to delete the rule and create a new rule.

Click Save.