Unless you have moved your Fallout 2 folder, this should be the process.
First, go to Computer, from there, open (C:) and click Program Files (x86).
After that, open the Interplay folder and open the Fallout 2 folder.
In the Fallout 2 folder, there should be three folders at the top: DATA, MANUAL, and sound.
Open DATA and three folders should be there: MAPS, proto, and SOUND. Open SOUND and a folder named MUSIC should be the only one there.
In MUSIC there are files with names like "01HUB.ACM". Left click and highlight all the files, and copy them.
Return back to the main Fallout 2 folder, and open sound, a folder named music should be inside. Open it and paste the files you copied from MUSIC.
After that, play Fallout 2 to test if it worked!