Kohler one-piece toilets have two seat attachment styles. In the first, the attaching bolts slide through and are accessible from the bottom side. These require nuts to be tightened to secure the seat. In the second style there is no access to the bolt. These have anchors built in to the toilet that the bolts screw into.
Remove the old toilet seat. Use the flathead screwdriver to pry open the bolt head covers on the hinge. Unscrew the toilet seat bolts and slide them out. If there is access to the underside of the bolt, use the adjustable wrench to hold the nut on the bottom side. This will stop the nut from spinning and allow you to loosen the bolt.
Wipe the uncovered area near the bolt holes using the antibacterial solution and cleaning rag. Over time, bacteria can grow underneath the bolt heads and hinge area of the old seat.
Place the new Kohler one-piece toilet seat over the bowl, line up the bolt holes and slide the bolts in.
If your toilet has no underside access to the bolts, anchors are built into the holes that you can screw into. If there is access to the underside, screw the included plastic nuts onto the bolts. Tighten the bolt from the top while holding the plastic nut with the wrench.
Push down the plastic hinge bolt covers until they snap closed.
Do not over tighten the hinge bolts or nuts on your Kohler one-piece toilet seat. The nuts are generally made of plastic and are easily stripped. Additionally the built-in anchors require special order from Kohler if broken.