The Handy THTS175 Instruction Manual page 13

STEP 11
Connect hitch bracket to hitch tongue using the drive pin Ø9x60.
NOTE: Hitch Tongue is adjustable to different lengths.
Drive Pin Ø9x60
Hitch Bracket
Hitch Tongue
STEP 12
Before operating the tow behind spreader make sure all hardware is securely tightened.
(*) Push the adjustable handle on Gauge & Lever assembly to the proper setting while spreading.
(*) Push the adjustable handle on Gauge & Lever assembly to the lowest position to stop spreading.