You appear to have created this post without editing the template. Please edit your post to Tell us what’s happening in your own words.
Learning to describe problems is hard, but it is an important part of learning how to code.
Also, the more you say, the more we can help!
Hi, welcome to the forum!
You are now learning to create a stylesheet. It is common to use this for all the ways you are styling your page, text etc. The system has automatically created a new document for you here. You are now asked to copy the styling elements you have already written from your main document to this stylesheet. Note that the opening/closing tags are not needed for the stylesheet.
Ask away if there is anything else you’d like to know.