We are trying to add metrics to all SQL instances we have in the estate, specifically we are trying to add "Page Life Expectancy" but i am struggling to find out how to do ti. 

This is an important metric when investigating performance and does not seem to be added by default. 

You can see from the post above that, the option is available if adding on single machine, however is not available when trying to add it to a template. 

Build 12200 MSSQL Backend.