To create a metric tag, click on Metrics in the left hand navigation menu, and click on the Metrics Catalog tab.
In the Metrics Catalog tab, click on the Tags filter icon in the upper right-hand corner, and then tap Manage in the drop-down. This will take you to the tag manager within Project Settings for all tags in your project.
Tap on the Create New Tag in the upper right-hand corner of the tag manager tab to create a new tag. Enter a name and description for your new tag. Click on Create.
From now on, you can quickly add this tag to any metric using the + icon when you hover on the metric. To see what metrics are associated with a given tag, you can reference the Tags tab within Project Settings.
Once you've tagged your metrics, you can zoom into Metric Lifts in Pulse for the tagged metrics to focus on the results that matter the most to you.