What should I enter in the blank except username and password?
"In addition, you must make sure the device cloud for the test account contains at least one discoverable device for testing purposes" <-- It's this mean that I should send a device of my company to Alexa?
Any reply will be helpful. Thx.
All you need to provide is anything that the certification might need to know to fully test your skill. For example, if you use account linking you'll need to provide a demo account to login with. For skills I've submitted that don't have any special requirements for testing, I've just entered "No special instructions".
At this stage, you don't have to send an actual device to Amazon.
But you have to add at least one device in the test account you provided.
This device can be virtual, just for Amazon to test if discover and control command is working.