How to set a folder name into a variable to use it in the same Batch file?

i want to make a batch file, This Batch file must look out, into a folder with the name "Draft" and for every sub-folder will be make a search for a .txt file "list.txt" and when finds this .txt file, Then will be execute a copy from the folder "Draft" to the folder "Ready". I have written a small script but i have some issues.

@echo off:loop  for /d %%i in ('dir "C:\Users\ntosis\Desktop\Draft" /ad /o:d /s /b') do (   SET a=%%i  echo %a%  )echo Folder is empty or does not existtimeout /t 15goto loop

The problem in this small part of the script is that, the variable "a" cannot save the name of the folder, if i change the echo %a% to echo Hello World then the script prints only one time the message and not as long as the loop runs. Any ideas?