The two lower supports are connected to each other with two support spacers. Connect the supports to the spacers using the included bolts. With the open end facing down, slide one upper support down into the lower supports. Repeat for second upper support. Connect the two upper supports to each other using the included spacers and bolts.
Slide one axle through the axle-rod slots on the upper supports. Before sliding it all the way through, slip on the two drive wheels. Repeat for second axle. Add a small amount of oil to all four axle-rod slots.
Slide the grip onto the end of the drive handle. Push the grip cap into the end of the drive handle. Secure the grip cap to the drive handle using the included screw, tightening it until just snug. Insert the shaft of the drive handle into one of the four axle-rod holes. Which one is purely a matter of preference. Drive a spring pin through the holes to attach. Drive spring pins through the holes of the remaining three axle-rod ends.
Lay the three drum panels end to end with the mixing fins facing up. Align the holes on the mixing fins of two of the panels and secure with included bolts and locking washers. Repeat for third panel. Place one end cap on a work surface. Bend the drum panel, mixing fins facing in, to fit inside the end cap. The drum will only be partially assembled as the door frame panel comes later.
With the door frame panel on a work surface, attach the included latch hardware using the included fasteners. Fit the door frame panel with latches into the end cap to complete the drum. Fasten the door panel to the adjacent drum panels using the included hardware. Position the second end cap over the open end of the drum. Working through the door opening, secure the two end caps to each other using the included tie rods and wing nuts.
Move the support frame to its final position, making sure that it will rest on firm, level ground. Place the drum on top of the support frame. Adjust the position of the drum so that it is centered and resting evenly on all four drive wheels. The ridged edges of the end caps should sit firmly on the gear sections of the wheel drives.