Create Table in Excel before using in Power BI or Edit Query in Power BI?

Hello everyone :-)

I'm new to Power BI.

The data that I wish to work with and display in Power BI is provided by a government source every 3 months in Excel spreadsheet format. I need to use data from several sheets within the Excel file.

The data is organised into aesthetic tables for the viewing public in the Excel file, but it is not the flat-format that Power BI needs (see image below).

I know that I must rearrange the table so that all columns of similar format are merged into one column (hope that makes sense).

Image from here.

Should I arrange the data into flat-format using Excel and the 'Create Table' feature? 

Or should I use Power BI's 'Get Data' function, and then use 'Edit Query' in Power BI? I'd love to be able to re-run the saved Edit Query steps when I grab the next spreadsheet in a few months.

Thanks everyone :-) I really appreciate those with incredible skills in Power BI helping new users like me with what I know may be simple questions.