Add a new rows to a custom table after dataset refresh

Two possible ways of going about this (probably more). One would be to use an R Script step in your query to snapshot the data to something like a SQL Server database using RODBC module. Another approach would be to leverage the PowerApp integration to manually enter the data after each refresh. There may be a Flow solution as well. Typically though, when needing to snapshot data, the R approach in the query is the way to go. You can then create a query to pull this data into your data model for use as historical reference.