Lower the existing blade so it rests on the ground. Remove the cotter pins that hold the blade to the pivot bar. Remove any trip springs and eyebolts. Leave the A-frame connected to the ATV and the pivot bar connected to the A-frame. Leave all the hydraulics in place---hoses and power angling rams with their pistons. Leave the lift chain in place.
Attach the included trip bumper to the flat plate in front of the pivot tubes on the blade. You may want to take a look at any diagrams on the instruction sheet to familiarize yourself with the parts' names. Coat the new pivot pins with chassis lubricant. Grease the hole on the blade pivot tube. Now you're ready to install the new snow blade.
Attach the blade to the pivot bar using the pivot pins, flat washers and cotter pins. Attach new trip springs to the pivot bar and blade with eyebolts. (Keep the flat end of each eyebolt vertical so hinging functions properly.) Tighten the locknuts and tighten the bottom nut. Install new eyebolt caps over any exposed threads.