Help with aylien extension

Hello,

I would like to extract entities from différent files (pdf I can convert in txt) with the Aylien extension.
Are there mandatory processes I must use before connecting the Extract entities process ?

I try many things and read all that exist on the Aylien website but I failed. The examples I found are not about extracting data from different files but from tweets or Excel files.

I would appreciate if someone could assist me, I would be a good student... 

Freddie2310