AsVIVA C25 Manual page 52

Step 6
52
Put the upper handle bar L ( 105 ) on the low handle bar ( 95 ) and fix it with screw M8 * 40L ( 104 ),
semi circle washer φ8*φ19*2T ( 23 ) and the nylon nut M8 ( 69 ).
Same procedure with upper handle bar R ( 108 ) and low handle bar R ( 100 ).