Here is how you can create your own custom metrics filter when using your attribution dashboard.
Navigate to the Channel Attribution page to view your dashboard and set your metrics.
Click on the upper right corner Edit sections > Create new to create your custom metrics filter
You may already see some sections already enabled. Click on "Create new" to create your custom metrics filter.
Enter a custom name and select which metrics to include in your custom metrics filter.
Click Create to save your custom metrics filter.
You will see your new metrics filter saved in the sections window.