Position the horizontal blind against the ceiling and center it within the window or frame. Mark where each end of the blind falls on the ceiling with a pencil. Set the blind off to the side.
Place the mounting brackets against the ceiling and line the brackets up with the pencil marks. Most horizontal blind brackets allow for multiple mounting locations. Position the brackets so the open end of the brackets face each other.
Mark the mounting holes on the ceiling by pushing the pencil tip through the brackets' pre-drilled holes, then place the brackets off to the side.
Drill holes large enough for wall anchors with your hand drill. Drive the wall anchors into the ceiling with your hammer.
Secure the brackets to the ceiling with the screws that the blind manufacturer supplied with the blind, using a screwdriver.
Slide the headrail of the horizontal blind into the mounting brackets. Slide the retaining clips into the brackets to hold the headrail in place.