How to use snapshot clause in the Query Service

Hello,

we have a requirement to keep the data in two datasets in sync. For some reason, we can't ingest the same payload in both the datasets. We are planning to leverage the scheduled query service for this. For the incremental approach, I think snapshot clause is the way to move forward. However, I am not sure where do I get the snapshot ids to use in the query.

Can someone please help here?