Define and tune elastic cluster

Elastic Stack Elasticsearch
1

Please provide steps involved for the below process

  1. Create an Index Lifecycle Management Policy for retention of 60days
  2. Create an ideal index template taking into consideration the existing cluster size and log ingestion per day.
  3. Define kibana.autocomplete cloud settings if required.
  4. Define ideal cluster size - number of nodes with capacity details for each component E-L-K
  5. Create a snapshot policy for 60 days retention of data.
  6. Review and revive the existing cluster health
  7. Define ideal cluster tuning guidelines - checks to be done for optimum performance.
  8. APM and ML Nodes configuration/receommendation
2

That is so incredibly broad that it is impossible to answer. You have also not provided any information about your use case or deployment. You generally have a better chance of getting a good response if you ask more targeted questions and show what you have done so far.

Meanwhile I will provide some useful links.