It's not your friend's application, it's your application. And you don't need any visa at all for a 1 month course. You are lucky they even gave you METV.
Are you asking about applying for your 1-year extension based on retirement, that you only do once per year? There's no piece of paper that would be stapled in your passport for your extension. You can apply for the annual extension 45 days early in Bangkok.
Are you asking about your 90-day report that you do every 90 days? These are not the same thing AT ALL. A 90-day report reminder is the only thing they would staple in your passport. You cannot go 3 weeks before this date. You can go 14 days early until 7 days after the due date.
Yes. Just be careful to ignore anything without the red asterisk, as without that it's not required and you can ignore it. But as soon as you click on it, it will become required.
Once you have submitted it, it should be linked with your passport. They will see it when they scan your passport at immigration, nothing further for you to do.