How to use(test) searchable snapshot?

Hi,

Recently I am testing “searchable snapshot” feature.
Actually I want to store local volume for latest few months data, s3 for older data
and search all data at any time I want.

But little confused and stucked.

I think test scenario is
create log-001 index
and insert logs to this index,
few days later, taking snapshot and rollover this index by ism.
so log-002 index created which is using same alias with log-001 index.
and user can search something from both log-001 and log-002.

Is this flow right?

I installed v2.5.0 (latest version) and
stucked first step, create index, followed official document.

Is there someone who tried this feature?

Thanks,