If you are used to using Final Cut Pro you will no doubt prefer to control your audio channels in the timeline rather than on the effects tab. At first this appear difficult if you use the button to the left of the timeline depicted here you shall reveal further controls in Adobe Premiere Pro.

This will allow you to control the levels from the timeline over time which is very handy if you have a soundtrack or voice over that needs to be taken in and out during your edit. Often these level changes will be clip dependent, meaning that if you move the clip around the point at which the levels need to change will remain the same. Sometime these changes in sound level will be relevant to the edit and if you move certain clips you will still require the levels to change at that point. Using the drop down here you have access to show clip toggles or show timeline toggles. Remember that clip levels works on that clips audio independent of the timeline and the timeline audio works on the timeline audio independently of the clips.

Add keyframes at the playhead using the black diamond next to the track or by using the Pen Tool.