I have just begun to learn Next.js and the video I was learning from shows a different file structure after creating a Next.js project from mine. In my tutor's video, in src folder there are separate folders for pages and styles that contains files like _app.js, _document.js, and index.js whereas if I create a new project I get a different file structure with a single folder in src named app with files global.css, layout.js, page.js only.
I am confused about why it's different & will there be any problems in my project if I move ahead with such file structure also I think _app.js is a really important file but its different in mine.