H-Rail and other top-loading style curtain rods don’t have a locking cam assembly. Instead, a molded shoe, attached to the bracket arm, slides into the channel at the top of the track.
Before lifting the drapery rod into place, slide the bracket arms with attached shoes into the top channel and position them along the track to line up with the wall mounting plates.
For Decorative Traverse and Heavy-Duty Drapery Rods featuring brackets with locking cam assemblies, there really is no difference between installing wall and ceiling mount - other than the Cam Assembly is mounted directly to the ceiling rather than on the wall plate (or arm). For Top-Loading or H-Rail track styles, ceiling mount brackets are usually completely different and may be extended or flush-mount.