If you click the icon that looks like a hand tweaking a knob(or holding a CD) then you will invoke the controller rack. It starts out as an empty window with an 'Add' button at the bottom. Click the button and an LFO controller will appear. Make as many as you like. To connect a plugin knob to an LFO controller, right click on the knob and a dropdown menu will appear. One of the choices is "Connect to Controller". Select that, and you'll see another window which gives you the option of two types of controllers: MIDI and User Controller. Click on the option for User Controller, and it will give you a dropdown list of all the LFO controllers you had made. Once you do that, click 'OK' and the window will close. Check your instrument plugin. The knob you connected to the LFO should now be moving on its own.

This form of automation is very convenient and can be used to change the way your samples and instruments sound, and it can be used for effects plugins as well. Something to also try would be connecting one of the LFO's knobs to an automation track, for an example, controlling a bass synth's vibrato in dubstep.