Counter panel using ElasticSearch datasource

Good day to you all.

I am quite new to redash and in this forum, but this is the first time I ever made a question here.

Let’s say I want to count the total docs in my index, how can I approach this?
Do I just have to make a simple query or do I need to define an aggregation first, counting the total documents?
Tested using PostgreSQL is quite simple, I succeded to get the value that I want.
But I have no idea as how to approach this on ElasticSearch, even on a simple thing like getting the total docs.
Hopefully someone here that has prior experience with this can point me to the right direction.