How Can I Edit Robot.txt in Micro.blog

Hello please I need help. I created my blog using micro.blog free domain then I added it to Google search console. But I got a report from Google that no page on my website could be indexed that my website has blocked Google crawlers by robot.txt.
Please help me resolve this issue.

You don’t have control over robots.txt while Micro.blog is in trial mode. Once you start paying for a blog, you can customize the file however you like.

When you’re on a paid plan, you can install my Custom Robots plug-in for easy access to edit the file.

Okay thank you very much