In Shape 17065 Manuel D'instructions page 22

Step 2
Insert the saddle post (10) into the socket on
the frame (01), and screw it securely at the
required height using the knob (08).
Push the saddle rail (11) onto the saddle post
(10) and secure it in place using the knob (09)
and a washer.
Fit the saddle (12) to the saddle rail (11) using
the provided multitool (23).
22
Step 3
Insert the handlebar post (14) into the socket
on the frame (01) and screw it securely at the
required height using the knob (08).
Fit the handlebar (15) to the handlebar post
(14) using screws (20).
Assemble the parts of the mobile phone
holder (19) around the handlebar (15) and
screw them together using screws (21, 22).