I am still not understanding can u help me out ?

I'm only relatively new to it as well so not the best to give advice, but basically the only frontmatter stuff that gets populated by default is what's in

root.schema.yml

, you'll have to create more schema templates which include the frontmatter attributes you want auto-populated upon creation. Have a look through the site docs for templates and schemas, there are instructions and vid tutorials - after doing it a few times it starts to make sense.

Like I am able to use the template stuff