Great news
Just some hints.
Always assume this gear all works and install it as such. Skip tests.
This is not a dress rehearsal this is the real thing.
Take your time make sure.
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All the connections correct are secured and can not move.
Derailer adjusted and so it cant rub against the hub wall gear face.
Battery attached rpoperly to the bike.
Charge battery.
Rear and front Axel bolts done up tight, all your might. Not flare the dropouts tight.
Goose neck and handle bars and seat posts are tight and other bolts n nuts. Dont put too much tension on the stem bolt.
Throttle grub screw tightened properly.
Brakes calipers, switches, (PAS) installed securely and adjusted
Torque arm in place and secured.
Brakes adjusted to centre and rim true.
Pump the tires to max can avoid rim damage on bumps. Maybe a little max under, not over.
Wear a helmet and
Take your time around people. I like to show off how slow it can go. These bikes can travel as slow as a snail. with delicate throttle control.
Good luck.
Recheck all the above.