SERVER - Mobile App and Web Server Communication

Hello,

I am developing a mobile application that needs to retrieve some data from a web server. I don't have any experience woth application to server communication so I am wondering what is the best way to impement this.

Talking in details, I have access to a third party FTP server. I want to acess that server and bring some data from that thord party FTP server to my server. Then, then I want to filter that data on my server and keep a copy of filtered data that can be accessed by a mobile app.

Can any body help me in this at very to level, likehow should be the architecture of overall system, etc..