If you need to edit the batch file later, browse to the Startup folder in Windows Explorer, right-click the file and click "Edit." Double-clicking the file will run the batch file immediately.

Is it possible to read from a txt file to get a value to use in a batch file. I'm able to do it if I know what value I'm looking for in the txt file, but I'm not able to read line by line ...

From the command line, type "backup.bat" and the batch file will run your specified commands: first, copying all files from that directory, then renaming them to remove the extensions.

B. Then extract all files from the third subdirectory to the first of the three levels (one level below "root" where the batch file is running).