For my college project, I'm developing an application that analyzes/detects anomalies in videos.

The backend is Python and the frontend is JS/NodeJS. I setup the backend so it runs 4 ML models and writes the outputs to 4 separate .txt files. I created a JS file that reads the .txt files and reformats the data to be saved as 4 .json files. Currently, the frontend just reads the .json files and displays the data... I run npm start to display the application in the browser at localhost:3000. Here is my problem:

In the application, the user can upload a .mp4 file and watch the video (react-player). I think I can setup a button interaction to execute a script that runs the backend .py file. However, I don't know how to continue from there. I need to exchange data twice: First, I need to download the video to the .py file local directory as input to the ML models. Once the models have finished running, I need to transfer the outputs (Python list or .json format... I know how to do either) back to the application so it can be displayed to the user.

I'm reading online that I can execute data transfer using jquery and/or ajax calls? Or maybe I setup a database? I have 0 experience w/ any of that so I'd like advice on the easiest approach. If you can recommend resources that can help me learn more on the topic, that'd also be helpful.