I think you should learn about programmable microcontrollers, which are key components used in this scale of robotics. Microcontrollers have the ability to read various signals and control other electronic devices. For example, you could write a script that sends a standard RC servo signal, upload it to a microcontroller, and have the microcontroller run the script to command the movement of the servo once it is powered. You should also be aware that there are various communication protocols, like I2C, TTL serial, or SPI. Various sensors or devices (like a pair of Bluetooth-capable devices) use various communication interfaces, and microcontrollers generally have the ability to use many of those interfaces to talk to the sensors.
By the way, since you are so new to robotics, it might be quicker or easier to learn by directly talking to someone in person about how systems like these work. So, it could be worthwhile to look around for a local robotics club (you could try Meetup) or a hackerspace/makerspace near you.