If you're upgrading your existing Hamboard, here's how it goes...
Remove your existing trucks and wheels.
Use hex tool and box wrench to loosen the bolts that hold the trucks on to the deck. Remove the wheels. Check the wheels and bearings for wear. If the wheels don't spin well, you may decide to replace your bearings at this time. Clean as necessary. Set-aside the existing trucks. Clean-off the deck, topside and bottom side.
Prepare your deck thru holes. (Skip this step for Classic, Pinger and Fish.)
The HST's come with M6 hardware which was one size larger than we used on the Biscuit, HHOP, Pescadito and Logger. You will need to enlarge the thru holes for the larger hardware used with the HST's. With a 1/4 inch drill bit bore-out the 8 thru holes on your deck, from the top side. With a 1/8 inch taper drill bit, countersink the 8 holes from the top side. This will allow the hardware to pull flush with the topside of the deck.
LOGGER ONLY (Skip this unless you're retrofitting your Logger.) The front truck needs to be moved back toward the center of the board by half the distance between the holes. (approximately 1 1/16 inch or 22mm). Drill 4 new holes using the trucks as a template. Do this at your own risk, we cannot guarantee that you won't screw it up! But if you do tackle this, you have our sincere respect. It's a challenge but really not all that hard.
Install the Block Risers
Place the 4 bolts through the deck and slide on the riser block. The wide part of the riser block is against the bottom side of the deck. The 4 holes in the riser block are not centered front to back. The shorter end of the riser block, with the holes nearest its edge, is oriented away from the center of the board.
Install the HST Trucks
Slide the truck down onto the four (4) bolts. This should be a tight fit. If necessary put in one bolt at a time. You may need to use a hammer to get the last bolt on. It's ok. NOTE: There is an arrow shape relief in the underside of each HST truck. That arrow ALWAYS points away from the center of the board and NEVER points toward the center of the board. This is critical, because the board won't ride right if you get this backwards. It may even be hazardous to your well being. Please take care of yourself and follow this rule.
Tighten the bolts with a M5 (or 5/32 inch) HEX tool and a #10 (or 3/8 inch) box wrench.
Install your wheels.
Remove the axle nuts on your HST. Remove one of the speed washers. Place your wheels onto the axle. Replace one speed washer and then tighten the lock nut so that it's secure but not so tight that it inhibits the wheel from spinning freely.