Reducing the volume of music when voice kicks in

Hi there
Hoping you can help me. I’m recording a voice over project. I have 2 tracks, one is music, the other is my vocals. The first few seconds is music only before the vocals kick in. The trouble I’m having is, how do I reduce the volume of that music whilst the vocals play and similarly increase it again when the vocals have finished?
I’ve tried doing it manually but its a bit a of a sharp dip - is there any way it can be reduced in a less dramatic way so it’s gradual?
Thank you!

You could use the “Envelope tool” (see: http://manual.audacityteam.org/man/envelope_tool.html)

Amazing! Thank you so much - I will try this.