To sit properly on a 3-wheel bike for comfort and safety, start by adjusting the seat height so your feet can touch the ground. Sit with your back straight and hands on the handlebars. Keep your feet on the pedals and maintain a balanced position. Make sure to wear a helmet and follow traffic rules for safety.
Could be a bad solenoid - jump across wires to test Jump smaller - (trigger wire) to cable that runs to starter
An electric scooter of all types use an electric motor powered by a battery(s) I have a 3wheel scooter and a 4 wheel power chair, both for medical use and use 2 - 12v Lead acid batteries in series to produce 24v DC which runs the 24v motor.