Hi Dan, so to use Orient there are going to be a sequence of 4 clicks.
The clicks are in pairs - the first click will place the orientation widget, and then it waits for you to adjust the rotation so you'll then do a right-click to exit that stage.
So it's going to be like this: Left click, right click, left click, right click.
It's probably those right-clicks that are confusing you - each of those right clicks is actually the same as pushing the "Done" button, if you look in the upper-right area of the window you'll see a prompt that is telling you what MoI is expecting for you to do next, that can help a lot just in general operation to look at that area so that you can get an idea of what is going on right at that step.
So start by selecting your headlight object (you may want to delete or hide the original source curve used to build it to get it out of the way).
Now run Transform > Orient.
The first click will be on the headlight, on the point that you want to relocate to be on the curved surface. Since your headlight is the same on the top or the bottom it doesn't really matter if you pick the top face or the bottom face for this, here I've picked a point in the center of the top face which looks like this:
After you've clicked there you can now adjust the base rotation, but in this case the default rotation is fine so you just want to exit this stage by pushing Done or right-clicking. If you look at the prompt in the upper right area of the window, you'll see it says "Adjust base axis orientation".
So after right-clicking (or pushing Done) you have now defined the base frame for what piece of the object will be placed on to the surface and also what direction on the object will be associated with the perpendicular direction on the surface.
Now comes the part for placing the target location. The prompt will now say "Pick target origin", so now go and click a point on your curved surface like this:
Now you can adjust the rotation if you want but the default is probably fine for you so just right-click or push Done at this point and you will be finished, getting this result:
Here's what it looks like in action:
But again note that there are actually 4 clicks being done there - left click on the headlight, then right-click to accept the orientation, the left-click on the target surface, then right-click to accept the target orientation.
A couple of things to watch out for - you can get messed up by snapping on to wires from the back side of the surface so you may want to turn off the hidden line display which you can do under the View palette with the "Display hidden lines" checkbox. Also similarly watch out for snapping on to the world x or y world axis lines as well. You may want to zoom in a bit on your target area so that you don't have too much of the screen taken up overlapping those axis lines.
Another thing is that picking the points like this will place the object to be kind of skimming along the curved surface and only touching it at a single point. So if you want to boolean the object you may need to push it in a little bit afterwards so that it is submerged a bit instead of only grazing at a point, or you can try to pick one of the orientation points to be sunken down in the one of the objects so that sunken-in point is used as the target .
Hope this helps!
- Michael