Converting orders in columns to orders in row with some data repeated

Hello awesome community,

Like many, my first post will be to ask for help and I'm sorry about that. I hope I can contribute more positively in the future

I am facing what I believed would be a classical problem with classical solutions but I have a hard time finding the proper way to do what I need.

It's a classic case of transforming a file containing orders in columns to orders in rows. Yet, as it combines adding empty rows and transposing only a part of the data, I am stuck.

You can see the data as I have it and as I want it in the attached file.

My apologies if the solution is out there already...

For a quick understanding of what I am looking for I also included the source/desired formats in pictures.
Source :
Source.png

Desired:
Desired.png

Thanks a lot for the help!

Thanks Alan,
I found out the Power Query option for Mac is only available when your OS is in the English language (I'm on a French Big Sur).
I have a virtual machine that can run Excel for Windows though, so any power Query solution would work.

Awesome, thanks a lot, the result looks perfect!

I'm not familiar with the copy/pasting of code so I watched the video but I wonder where I can access the code? Is it accessible in the PQ Transpose.xls (I can't seem to find it there but I'm looking at it on a Mac for now, maybe it shows only in the Windows version).

Aaaaaannnd that worked perfectly, thank a lot !!!!!