How do I create a flutter project despite the error "At least one platform must be selected"?

Known issue (caused by flutter/devtools#2653), please see https://github.com/flutter/flutter-intellij/issues/5230#issuecomment-771279236 for a workaround

Problem is with 53.0 version of Flutter plugin for IntelliJ. You need to install previous version.

1. Download Flutter plugin from this link (https://plugins.jetbrains.com/plugin/download?rel=true&updateId=107561)
2. Open IntelliJ
3. Go to Settings
4. Click on Plugins
5. Click on Settings icon at the right corner of navbar
6. Click "Install Plugin from Disk..."
7. Select .zip file of Flutter plugin you just downloaded
8. Restart IDE

This works for me, hope this will solve your problem.

Just the temporary solution create project with cmd

flutter create my_app

must have flutter environment set in your OS. Then open with intellij project by browse my_app directory.