Do you mean to say that you want to enable all of the metrics available in snmpcollector template with a single click of a button? Not sure we have such an option from the GUI other than selecting one metric at a time from the Template Editor which is painful .
Also just a piece of advice ..it would be a crazy idea to enable all of the metrics in a template if you have large devices being monitored and if they are in good numbers . The QoS would quickly fill up your DB.
Recommended option is to enable only the once you need the most for monitoring