How to change the cluster health status from red to green

Elastic Stack Elasticsearch
1

How to change the cluster health status from red to green, are there any commands used to do so.

2

You should check your logs and various _cat APIs to see why things are not green.

3

how do i check _cat APIs

4

If you're running Elasticsearch on you local machine, type this in the browser: http://localhost:9200/_cat/health

Reference: https://www.elastic.co/guide/en/elasticsearch/reference/current/cat-health.html

5

Thank You.I'll try it out.