Within Cubase you can do what we call automation. You can do this for everything, your VST instruments and effects as well as pan and volume, etc.
The easy way to start with this is to create an audio track and record something. When finished, go to your cubase mixer. Go to the fader for the track you recorded. You will see next to it a R and a W. R means read. W means write. Rewind your recording, then click on the W. It will turn red. Then click play. As your music plays, move the volume slider up and down. (since you clicked on the W, it is writing your volume automation). When your music is finished, click on stop. Then rewind. Then click on the W to deactivate the write, and then click on the R and it will turn green…it will now be reading your automation. Click play, and you will see your fader move up and down.
Now go out of your mixer and back to your audio track you recorded. Look at the bottom left of your track and you will see a +. Click on the + and it will expand the track downward. You will see more +'s. Each one is an automation lane. For example, you can choose the Volume automation to automate volume. I think it is the first or second one. You will now see a line that looks like a graph. Each “dot” on the graph is a change. You can move those dots left and right, up and down, delete them, or click on the line anywhere to add them. This represents what you saw your fader doing when you played it back. If you want to change things here, you have to have the R enabled.
If you want to start by drawing, assuming you did not click the W and play and write, and it is just a fresh track recorded, you can go straight to the automation lane, click on R, so it will read, and you can add your changes from scratch.
Hope this helps.
Ohhh…if you are talking about interfacing with a physical hardware mixer so your mixer will physically have the faders go up and down and such, you need a mixer with motorized faders. You would do everything I explained above in cubase, but you would be using your faders on the mixer to read and write instead of the cubase software mixer. Beware, not all motorized fader mixers are touch sensitive. Touch sensitive means that after you “write” your automation a first time, and you want to “Try again” to tweak even more, when you grab the fader reading what you already wrote, the second you touch the fader, everything you do will be the new movements until you stop touching. There is a very cheap automated mixer out there, but it is not touch sens.