Thank you for your post!
If you create a FileMaker Database with the four fields, you should be able to import the records from each CSV file individually. You would end up with the data from every file. You might see Importing data into an existing FileMaker Pro file.
I'm also going to move this thread from the FileMaker Community Feedback Space (which is specifically for input on the Community itself) to the Discussions Space where you should receive more views and potentially more feedback on this topic!
Thank you TSPigeon, my thread is resolved, I'll take in account de Discussions Space for future requests