Can't hear the 2nd voice on my recording. Help!

Hi all!

I recorded a skype conversation without using my headphones; hence, I can hear my voice extremely loud but can hardly hear the other 2 voices speaking.

I tried selecting a section where only the other 2 voices are speaking and amplify the sound, but it does not work.

What can I do to make it work?
I need help, please!

I’m new to audacity so I have very little knowledge on how it works.
I was trying to separate the sound levels and focusing on the lower ones in order to amplify them, but now sure how to do them.

If you have suggestions, please let me know.

I need to do this today IF possible.

Thank you for your time and help!

Effect > Compressor (though Effect > Amplify on all the individual quiet parts should work too).