Match Move or tracking in general is not really available in FCPX from a Motion Template (without external software like CoreMelt's TrackX/SliceX or similar products hyping "Mocha"). These types of plugins are actually programmed with FxPlug (and since I thoroughly hate dealing with objective-C, I don't deal with it personally [...maybe if they put together an API for Swift... not holding my breath]). None of that means you have to get one of these products and you can use Motion straight, handle your tracking needs and either export the result to a "movie" file or publish a "one-time-use" generator to FCPX. Once you're finished using the media to handle the tracking you can discard it from Motion and just use the tracked objects as an overlay (you will not want to save that media with a template if publishing a generator to FCPX). The only issue then is syncing up the generator with the media.
So: the workflow
Export the Range you want tracked from FCPX. If you're just using a regular clip that you imported into FCPX, you can just import that same clip into Motion.
Make sure the Project Length is at least as long as the clip. You can adjust that right in the main UI by clicking the little clockface icon next to the timecode/frame counter info under the Canvas, then click-drag the time up to increase the length of the project—you will see a blue bar under the canvas indicating the media for that layer and you will be able to tell where it ends as you increase the time of the project. You can click on the clockface icon again to go back to the timeline time indicator.
Apply an Analyze Motion to your clip. You should see a small yellow circle with a cross-hair in the middle of the Canvas. Click and drag that marker to the location you want to track [actually, you will typically choose a spot near the point you want to track - you need a good high contrast "mark" the tracker can easily follow (this is going to take some practice on your part to learn what works best - every clip is different and there will usually be "breaks" to deal with)].
Click the Analyze button and Motion will start advancing the clip frame by frame and laying down little white points strung along a red line. If and when the little white points start going astray, Motion will usually stop playback. Move the playhead back a few frames until the track matches again, then drag the yellow circle cross-hair to a new tracker point. Click the Analyze button again and Motion will continue. You can go back and forth with this process to "refine" the track to better track points, etc.
What to do when what you're tracking moves behind another object and cannot be tracked? Move the Playhead to a position when the object reappears and continue the Analyze process. For the "frame" dots in between, you can zoom into the Canvas and manually move them (frame by frame) to new spots to create a movement interpolation. You will see the white dots that can be moved slightly get larger and you can only move the dot that belongs to that frame - so make a "best guess" as to where the location is if the object is obscured from view (or FIX an errant track point as needed).
Create the object (if you haven't already) that will follow the track and add a Match Move behavior to it. Click and drag the Analyze Motion behavior from the clip layer into the Source well of the Match Move. Go to the first frame of the the track and drag the Match Move object to the location you want it to be "offset" from the track.
At this point you can export the clip as a new clip to import into FCPX, or delete (or turn off) the clip in Motion and Publish Template as a Final Cut Pro Generator. (If you just turn off the clip, deselect Include Unused Media in the Save dialog). Apply the generator in FCPX (it should be easy to sync to the clip - just line it up with the beginning of the original).
Sometimes auto-tracking can be useful. However, if you're really practiced at it, it is very much faster to manually track objects in Motion (I don't care what software you use - I've used TrackX and SliceX - I wasn't impressed). You can even do manual tracking in FCPX if the objects you want to follow have their position (and possibly their rotation and scale) parameters published. For that technique, its as simple as setting the first keyframe, advance the playhead by 10 frames by typing Shift - left/right arrow and moving the object to it's new location. You can refine a track by moving the playhead between keyframes and making minor adjustments. It's quicker and much easier to interpolate positions when the tracked object is obscured; but it is a little tedious (and less glamorous than using the fancy tracking add-ons).
This example took 3 keyframes (first, last, and an adjustment in the middle):
... just sayin'.
