Which should I use on my DB? - Clustered Index or Non Clustered Index or Both I just need advice on how I am going to optimize my database.

| Date | Time | Area | Block | Data1 | Data2 | Data3 | DataN |

I have that format of tables on my database. Each tables has 30-days of records with hundred thousands of records each data. Uploading of data to database is every morning. The data of yesterday will be uploaded.

The most common queries to run is grouped by Date or Date and Area or Date and Area and Block. Now, in order to make queries faster, I found out using indexes. I used indexes before. But that was when I am using a primary key. In this table, I didn't use primary key because it is totally unnecessary.

Now, I am really confused on how I am going to optimize this. Based on this reference on Column Considerations part, clustered index is not a good choice on Columns that undergo frequent changes. I am really confused.

Please help me if I need to use clustered index here or just non clustered or both.
1/ If after upload you do not update the data, only delete the rows older than 30 days.

2/ And if you can sort your file for the upload by Date, Area, Block

=> Then a clustered index on Date,Area,Block will greatly benefit your aggregations on Date, Date + Area, Date+ Area+Block .

It will also help any request with a where condition on Date, Date + Area, Date + Area + Block , whatever the selected columns for the request.