Hi,
The first action is to unsnap both sides of the removable flap that is between the side of the door and down to the base of the top. While doing that you are already starting the procedure to lower the top. Unsnap the top down to the base of the top.
It really makes it easy to have a helper for the next step. With a party on each side remove the nut at the top of the windshield post. Save the nuts and any spacers. Raise the top in front and push down on the top frame near the middle. Now remove the cotter key on each side that holds the ends of the center bow. While holding the ends of the center bow move them to the alternate location on each side. Now you can continue lowering the complete top back and down where it seats on the top bow holders. Use the strap to secure
all the folded top material. If you have the dust cover it can be installed now.
It is suggested you purchase an Owner's Manual, a Maintenance Manual, the Chevrolet Service Manual set and some selected Sales Litature. Assuming you do not have any of those pieces. They are all available in reprint at a reasonable cost.
Wish you good fun with your sporty Roadster.
