basically i am beginner in web development and i am learning web development and i learned html css js and created some projects with them.Now i am heading towards backend development where i am learning node js express js mongodb but i have question that till now i created website using html css js and opened html file just clicking on it in the browser. In backend development like i am learning express js so we install express then define routes and render html and some more stuff. so now my question is that now whenever i have to create a website first i will create the frontend and then in order to make that website have some database stuff we have to add backend so in the end the backend serves the frontend ? like in my case i am using express. so now whenever i need to start any website is i have to start the express app first and then render the frontend with it ?