Help me under lifecycle policies with namespaces

I am having a very difficult time understanding the workflow with index aliases. I understand ILM as what it is doing with the indexes with shrinking shards, moving to warm/cold/frozen tiers and deleting after X amount of days/size/time but what I can't wrap my head around is the purpose of index aliases.

For example I have multiple policies with INDEX only that uses namespaces. This will automatically create new hidden indices with names such as along with data streams. However these default index templates that come with elastic have NO aliases. So when I try to add a life cycle policy to them, they show a warning:

Index has no aliases
Policy 7-days-default is configured for rollover, but index .ds-.logs-endpoint.diagnostic.collection-datacenter-2022.05.12-000001 does not have an alias, which is required for rollover.

I figure I wouldn't want to edit a default index template that comes with Elastic but even if I did what would I put as a index alias especially since namespaces are involved? What is the solution?