Hello Samuel,
first follow some training about general B1i (available on the partneredge or search on the internet).
Also SDK/DI-API expierence is needed for use this with the object of SAP Business One.
In b1i you have an atom which you can read an ftplocation and get the filelist. After receive the filelist you can get the files from the FTP location and process them (into SBO).
Hope this helps.
Best Regards Teun