I have a problem with creating a router connect to file in another directory. there are 2 folders containing code in my workspace is "code FE" and "code BE". The code FE folder contains the HTML and CSS files that have already been built. now I want to build the back-end and create a router to file in code FE (example here is register router and login router). Additionally, I want when I click on localhost:3000, It will give me to the home page. and when I click to signup button on the home page, it will give me to register with a router like 'localhost:3000/register'. sign in too. How can I do all this. here are directories in "code FE" folder

file index.html is the main page. CSS file in asset folder and here are directories in "code BE" folder

page.js is where I set up a router

everyone please help me!