Check that the window and AC unit sizes are compatible
Gather the AC unit, side panels, screws, brackets, and tools
Turn off the AC unit and unplug it
Open the window fully
Install any support bracket if required
Place the AC unit on the window sill
Center the unit in the window opening
Lower the window sash onto the top of the AC unit
Extend the side panels to fill the gaps
Secure the side panels to the window frame
Fasten the AC unit according to the manufacturer’s instructions
Tighten all screws and locks
Seal any remaining gaps with foam or weather stripping
Make sure the unit tilts slightly outward for drainage
Plug the unit into a grounded outlet
Test the unit to confirm it is secure and operating properly