how to have a different design on front page

Hi,

Hello everyone. I’m new to wordpress but I know html,css. Anyway, I want my first page to look different than the other pages.

I’d like my welcome page to look something like this

https://test.nattywp.com/preview.php?theme=folium

and the rest like normal pages with a small header. If i edit index.php that would affect all the pages. what do I need to do to create that welcome page? Any tips, guides, would be much appreciated.

thanks,
milo