Remove the wand and apply the film
Cut holes in the shrink film so you can access the wand and lift cords. Start by removing the rotating wand from the blinds before you apply the shrink film. To unhook the wand, lift the retaining ring (if any) and lift the wand off the hook. Apply the window film, shrink it in place, apply tape and cut holes.
Install the wand and pull out the lift cords
Once you cut the holes you can reinstall the wand and access the lift cords.