Don’t click on “Start a post”. Click on “Write article”.
Click on “Manage”, choose “Settings”.
I presume that the title of your article is already optimized for SEO and GEO. In that case, you don’t need to edit the URL.
What you need to edit are the SEO title and SEO description. Obviously, this is no place to explain to you all the rules on how to do that.
If you don’t know them, I suggest you use AI to create them. Just mind the maximum character count.