I am a Window user, I don't have MacOS. So to participate in the challenge, which tool (IDE, etc) is recommended for Window to build the app? Thanks!
Build Application in Window OS
What challenge? What app? Please provide some context for your question (more than "Organizer Window")...
If you're referring to the WWDC22 Swift Student Challenge, the required software is stated in the requirements:
Your Swift Playgrounds app project must be built with and run on Swift Playgrounds 4.0.2 on iPadOS 15.4 or Xcode 13.3 on macOS 12.3. If it runs on iPadOS, it must be optimized to display properly on all models of iPad Pro. You may incorporate the use of Apple Pencil.