If you are unsure what layer you want to attach the tracking data to, or want to apply the data at a later time, choose Raw from the Tracking Type menu bar. The tracking data is stored in the motion source layer, where later on, you can use expressions to link a target layer.
If you have a layer in your composition that you want to attach to your tracking data, the tracker will default to using Transform as the Tracking Type. Transform tracks position and/or rotation with one-track point for position or two for rotation. Choose the layer you want to apply the data to in the Edit Target bar.