Official steps: open the parking stand, expand the stand pipe and keep the scooter stable; connect the handle with both ends of the power cable inside the stand pipe and route the cable into the stand pipe, then install the handle on the stand pipe; lock the screws with the 3mm hex tool included in the package; after assembly, connect the charger and wait 2-3 seconds for battery activation before the scooter powers on. Manual warns: do not turn on the power before installation is complete, and use appropriate force to avoid component damage.
Fuente oficial: https://manuals.plus/yadea/ydx1-eliteprime-x1-electric-kick-scooter-manual (tier C). Traducción/paráfrasis fiel del manual oficial; no se ha añadido ningún procedimiento no documentado.