I have tried to search samples with Import->Freesound->Tag but nothing happen, I must setup something to do it, I haven’t found anything in the Preference box.
I’m on Ubuntu 15.10.
Freesound changed their login/authentication system and threw away the old one. The code in current Ardour releases therefore fails to work.
We have a development branch which has support for the new Freesound authentication system, and it will almost certainly be merged into the next release. Until then, there’s no way to get Ardour to connect to Freesound.