You need to write the front end and the back end for your platform
The Front end - It it's the part that gets displayed in the browser, for that you probably want to use some framework like React, Vue or Angular because it's easier. You need to know HTML, CSS and JS to write a good front end.
The Back end - It's the part that handles your platform logic. For that you can use almost any languague you want(Python, node js, java, ruby, php), you also need to connect to a database to store your data.
Some popular options are: React and Nodejs, React and Java(using Spring), Angular and Ruby
You can watch this youtube playlist to learn how things talk to each other. If you need some help feel free to contact me
The Front end - It it's the part that gets displayed in the browser, for that you probably want to use some framework like React, Vue or Angular because it's easier. You need to know HTML, CSS and JS to write a good front end.
The Back end - It's the part that handles your platform logic. For that you can use almost any languague you want(Python, node js, java, ruby, php), you also need to connect to a database to store your data.
Some popular options are: React and Nodejs, React and Java(using Spring), Angular and Ruby
You can watch this youtube playlist to learn how things talk to each other. If you need some help feel free to contact me