Creat a new page template and add custom css/js/images

please teach me how to create a custom pages with my own css files
its seems like the <link stylesheet tag gets overided in the page code
where to add the stylesheet and js scripts ?
thank you

See “pushing assets to the browser” in the documentation:

As for writing your own link tags, that should work too, there is no reason it would not if the link tag is explicitly in the template. But if you push the assets to apostrophe they will get minified and combined in production and your site will be faster.