Try curl -XPUT ESHOST:9200/NEWINDEXNAME -d @mappingfile.json
Check out the documentation too, it has practical examples using Kibana Dev Tools, or you can copy them as curl commands 
If you want the mapping to apply to more than one index, then take a look at index templates,
You don't need to refresh the index mapping in Kibana settings unless you make a mapping change in Elasticsearch.
Excluding fields can improve performance, but if it's only a few then it may not be worth it.