The Thumb throttle controller means which you could change the pedal-aid on/off with the force of the button. Many of the kits bundled over are wheel conversion kits, which means introducing the electric motor to either the front or rear wheel. These kits are rather very easy to set up, https://medium.com/@usamach4969/top-rated-best-conversion-kit-electric-bike-that-will-take-your-ride-to-the-next-level-find-the-52241c7abf28