Experience... I've made many things with these motors and controllers before, but never Bluetooth. Almost no experience with Arduino.
Robin2 is echoing my earlier advice--develop the motor control and the serial communication before adding the Bluetooth. There is plenty of information available about using the Arduino for motor control and communicating with it through the Serial monitor.
Regarding the BLE (Bluetooth 4.0, Bluetooth Low Energy) which is required for the Apple ios, my advice is to go with an integrated solution using an Adafruit Feather 32u4 Bluefruit LE.
There is good support and tutorials available. It is designed for battery operation. There is a second hardware serial port available so you can avoid software serial and develop your code with both the monitor and bluetooth active. The Feather option is not going to be the lowest cost, but I believe you will be more successful than with adding an HM10 BLE module to a base Arduino.