The
left slingshot. Nothing special to do here. 
The
right slingshot. You will need the top nut to be loose to install the
right target protector.
The
left target bank protector. Put the hex screws through the protector and
the plastic, making sure it is all aligned before you tighten it down.
The
right target protector is the most difficult one to install. You must
remove the racetrack. Do not remove the screws at the top of the track.
They have a loose nut plate inside the box, which is hard to put back
once it falls out. Instead, remove the screws that hold the plate to the
backboard.
The
left engine plastic. To install this part, you will need to remove the
engine cover, two pairs of screws front and back. The engine cover clips
into guides.