200,- EUR One-time payment for students

• What is this one-time payment for?
• When and where can I apply for the 200,- EUR?
• Until when can I submit the application?
• Am I eligible to apply for the 200,- EUR?
• I have already received the 300,- EUR energy supplement from my employer, may I now apply for the 200,- EUR?
• What is the BundID and how can I get it?
• Where can I find more information?
• I have problems with the application, who can I contact?