Hi
I took your question and typed it as a search in bing and it came up with many examples. But it does sound like you are just asking us to build it for you.
It helps to do some searches and try to piece things together a little, so you can come with specific questions instead of asks to do the work. We want to help you grow, not do all the work for you.
Take a little time, do some searches, try a few things, put a little effort in and we can absolutely help you get there.
Think about
1. How often do I do this?
2. Where is the Excel file stored?
3. Am I going to be updated existing fields each time, or adding new or both?
4. Am I recreating a new excel file based on a template?
and so forth.
5. How does this excel get where I am processing it from?
6. Do I need to move files, rename files, etc.
The basic structure you need and this is a simple manually triggered flow.
1. Manual Trigger (Instant Flow)
2. Add a SQL Get Rows running your query or executing your Stored Procedure
3. Do an Apply to each to loop through any records
4. Inside the loop, try to add or update Rows in a Table (for Excel)
That is the simple flow gyst of what to do.