One thing that might help, turning on "Show axes". They are depicted with three coloured arrows — red, green, and blue (you can remember "rgb" — they coincide with "xyz", as in the red arrow is along the x-axis, the green arrow along the y-axis, and the blue arrow along the z-axis. They point towards the positive side of each axis.
When you have a camera (or other item) selected in the editor, the numbers in the middle row of the "Position" section are the x, y, and z coordinates of the current selected object with respect to the ship's 0,0,0 reference point in meters. That's usually the middle of the ship, but doesn't have to be.
The two rows of numbers above and the two below the coordinates are actually buttons. You can use those to adjust the current coordinates. Holding down the shift key will allow some larger movements. You can of course, just type in numbers.
The second group of numbers shows the rotation of the object or camera around each axis, relative to its
own centre, not the ships!
In this pic, the selected camera is number "4", a cockpit camera. It is the yellow object towards the left of the screen (it actually flashes between red and yellow, I do believe, as the selected object) — a sphere inside a cube. The view is from one of the other defined cameras — the red grid is the view from inside the camera object sphere. It is also rotated, as you can see by the numbers in the Rotation parameters — pointing backwards.
If you want to drop a camera near the surface and you are at 10km altitude, enter 10000 (or -10000) in the axis that is up/down for your ship. For example, in the pic above, I would put -10000 in the y-axis box (green is up/down on this ship, and negative is down). You may also want to let it trail the ship by a fair bit too, up to you. Another big number in the forward/backward axis — in my case would be 10000 in the z-axix to place the camera 10km behind the centre of my ship.
And, if all you want is to look left and right, or behind and down also, no point in defining extra cameras for that, just make the one, then if you want to look left or right, just change your view with the ctrl-numpad keys — if you let go of the ctrl key first before the number key, the view will stay locked in that position until you press another view key. For example, press and hold the ctrl key, press the numpad 6, the view will rotate 90 degrees to the right. Let go of the 6 first, and the view will switch back to forward view. But if you let go of the ctrl key while still holding down the 6 key, the view will lock to that view. Press another view key combination ctrl-6 again, ctrl-5, doesn't matter, as long as you release the number key before the ctrl key, and the view will unlock back to the forward view. You can do that with left, right, up, down, or behind views, no need to waste camera definitions if all you want is 90 degree options.
Hope that helps.