Hey !!
Here is the French guy !!!
hello H444892 !! I'm sorry, but I don't take trainee... because I still considering myself as a trainee...
You have
http://www.reiche-trommelbau.de/ in Germany, maybe you can try.
But really, I think it's very difficult to find (I tried too few years ago...)
To my mind, you can learn how to make congas if you work for a barrel maker who is OK to let you make your drums in his factory after the day of work, and you learn by yourself how to make Hardware and skins. Or you learn everything by yourself.
Personnally, I have learned by myself. I make congas repairs since a long time, it's a good way to see how all the old drums are made (the better way). And I tried to make my first own drums with an old barrel.
My advice : try by yourself, and if you have questions about repairs or making you own drum, post it on the forum, I think you will find some help !
Gaƫl.