Getting file from FTP and organizing it

I’m having difficulty in showing the contents of the FTP file I fetched from the FTP module. I already connected the FTP server and established the path. But what module should I use next in order for me to see the contents of that file and organize it into an excel sheet or CSV format?
The file I’m trying to fetch is a .txt file of my supplier’s product catalog. I want to convert that file into a CSV format and add headers then filter the categories that I only need.

Can you guys please help me on what should be the sequence in our scenario.