Step one. Make protective copies of both tracks. Separate USB sticks works well. Assume the computer is going to go face-first into the mud and take Audacity and your show with it… permanently.
Both audios are in my workspace at the moment
What does that mean? I don’t think Audacity will open up a link or a network mount (but it might). Import both shows and they should appear one above the other and play at the same time. You can steer that with the MUTE and SOLO buttons to the left.
One way is just to drag-select the good intro, copy and paste it at the beginning of the good interview. Yes, you will have two intros then. The usual copy and paste keyboard buttons should work. I would probably Save a unique Project when you do that. You can go back to that point if you really mess something up.
Audacity will not save UNDO. Once you close Audacity, that’s the end of the UNDO listings. The current show, your old backup Project and the original shows are all you have.
Then go in with the zoom tools and cut out the bad intro little at a time. If you overdo it, you can Edit > UNDO and back up, or trash everything and open up that Project you saved in the last paragraph.
You can go crazy with the zoom tools, but I only use three. Drag-select a portion of the show and zoom into it with Command-E. If you go in too far, zoom out a little bit with Command-3. Zoom out to the full show with Command-F.
http://manual.audacityteam.org/o/man/zooming.html
There is a change to Audacity display you might want to make.
Audacity > Preferences > Tracks > Display > [_] Update Display… (de-select)
Normally, Audacity keeps the screen up to date with a recording (do select update) so you can continuously see the current state of recorded volume and time. When you edit, however, that checked setting can steal your edit view away from you, usually at the worst possible time. You can slide the timeline view back and forth manually with Shift + Scroll Wheel. Or use the Zoom tools.
When you get one of the tracks perfect, select it by clicking just above the MUTE button and File > Export Selection: WAV (Microsoft)… That’s your edit Master. You can make an MP3 also if you want, but you shouldn’t do production in MP3 because of its sound damage.
Koz