How to make custom template out of default Filebeat template

[ORich (Richard)]

Dear all,
I setup a new template as follow to distinguish filebeat file names. The problem I have is that this new template has no mapping configured ... how can I make this new index template inherit from default filebeat mapping ? As you can notice in the screenshot, the M square in the content column is not blue = no mapping
Thanks and Best Regards.

PUT /_template/filebeat-7.10.2-webcomws
{
  "index_patterns": ["filebeat-7.10.2-webcomws*"],                 
  "settings": {
    "number_of_shards": 3,
    "number_of_replicas": 1,
    "index.lifecycle.name": "datastream_policy_30d",      
    "index.lifecycle.rollover_alias": "filebeat-7.10.2-webcomws-alias"    
  }
}