I'm working on a project with a loop and four other audio tracks and want to automate a fade out with the master bus. I can do it with the master fader but I want to manually manipulate the points in the fade. I don't know how to put the master bus into the timeline however. Any help would be great -thanks

All buses should be in the timeline automatically including the master bus. You probably just need to open the buses in the Track view.

At the bottom of the track view, there is a hidden area where the buses are located. To see them hit the keys
SHIFT + B to show the bus Pane while in the track view. 
 
The master bus preview is just for show or changing the color of the wave form There is nothing you can do with the buses wave form. 
 
The other option is to bounce your entire project down to a single track and then add your Fades there.

Jesse G
...There is nothing you can do with the buses wave form. 
 
The other option is to bounce your entire project down to a single track and then add your Fades there.

 
It would be much easier to use bus automation, which is what I suspect that the OP is intending to do anyway.

Yeah, I mean you can definitely automate the buses.