This is a great kit to get started with. Keep in mind this is not plug and play. There is only one connector that is guaranteed to click to ANYTHING and that is only for the motor hall sensors. The motor phase wires (thick blue, thick yellow, thick green) attach to the yellow/black bus block with the 5 screws, along with the thick red/black wires for your battery.A few tips if you are mounting this to a Razor MX500/650 or RSF:First, on the motor, you need to remove the 3 phillips head screws and lightly counterbore the holes until the screw heads sit just below the surface. Use a drillbit that is slightly larger than the screwhead. There is a video on YouTube from "MarleyJax Garage" where he shows the complete install for a kit like this and shows this portion in detail.I highly recommend to get a lithium ion battery that matches the voltage for the motor kit you're buying. If you use SLA batteries or add more SLA batteries to get higher voltage, you will have terrible battery life. After I got this kit running, I put in an order for a lithium battery set just a few days later. It was horrible.Yes, there is a 3 speed setting. If you do nothing with this connector and just leave it hanging, the motor will run at full speed. If you want to use the speed selector, get a throttle with 3 speed switch. It will probably connect. If you want to limit the speed without a switch, you can do this with a paperclip. Put one end of the paperclip into the black wire (middle) and then jump it to one of the other wires. I forgot what colors they are and which color gives you medium and low speed. If you put it on low speed, it will dramatically improve battery life. The low speed is still much faster than stock.The acceleration might be neck-breaking for a child. The original throttle and motor controller do a great job of gently easing into the acceleration. With this controller, the second the throttle engages it is pretty violent. It's not a deal breaker. Just be aware of this.If