changes not being saved ??

I am new to DeskTOP BI but an Excel guru. I thought this would be easy, ha ha ha.  The interface isnt easy....

I load a csv from my PC. It seems fine except, header row is being treated as data. Dumb program, it is a csv.

Anyway, I used a query to "delete" first row and renamed cols from "colum 1" to appropriate. same to other cols also.

Now the problem, I save it as a pbix file, BUT when I come back and open this file, the header row is present and cols are back to "column1 " etc.  In short, my changes were not save.

Now I am afraid to do anything meaningful since changes are not being save.

Whats up??