How to import audio

[jfjfjf]

New in the forum and with Avidemux.
English is not my native language.
I thank in advance for your patience with me.

Mp4 video - audio with many noise in silent parts.
Video converted to avi and the wav audio extracted.
Extracted audio was cleaned up with Audacity.

Now I don't know how to put the cleaned audio in the original video.
Some guidelines in the Internet give the path "Audio> Main Track> External audio" or something.
My Avidemux QT interface shows "Audio > Select track" without any reference to "external".
Could someone help me on this topic?

Thanks to everyone who can spend time with my problem!

[Jan Gruuthuse]

with 2.6.1 Main Menu (not on left hand side) -> Audio -> Select Track -> Audio Tracks Configuration:
Track 1 [v] Enabled [Track 0 from video (..... ) ] <- select here [.... Add audio track]
[Select audio file] Window opens, browse to new audio track, select the audio file and click [open]

Track should now show: [File ......]