Upgrade Elastic stack from 6.2.4 to 6.4

Elastic Stack Elasticsearch
1

I have actually two versions (6.2.4 and 6.4 ) Elastic stack in my two environments (DEV and PROD).

I want to upgrade 6.2.4 to 6.4 version. Somebody can help me, to know what is the good process to do that, please. I have read documentation, but , i not hundstand it well.
Thank you

2

If you can elaborate on what you may not understand then we can help with that.