The component tab, pertains "Specifically", to the lower Tab you have selected, and the selected location (highlighted), there in.
e.g. If the "Physics tab>Fuselage>Fuselage" is selected, the "Component>Add" will give you, a list of physical components, you can add, to That Parent.
Like a Camera, or, Movable Pod, Camera.
Add, and Adjust to your specified X,Y,Z coordinates, angles, etc. Movable Pods require setup, for movement control.
Load the Stock "Quadcopter". In the editor, you can check out a camera setup, with Tilt Ch 8, and Swivel Ch 6. Reverse Engineer to fit your needs.
Note Stock Aircraft files are protected. You cant screw up a stock file. If you make changes to a stock file, before you are allowed to exit the editor, you are prompted to Name the "New File". This will Create a New File, while Preserving the Stock, Unchanged File
If you leave the editor, with out saving files, no harm, no foul. Files will revert back, to the state they were, when you first opened the Editor.