I was told that the first steps in creating a synth is creating oscillators that produce an audible signal I see that juce has DSP module that include an oscillator how does one implement one within the audio plugin app creater the base classes created are a constructor class destructor class prepare to play class processor block class and then save state and refresh state what do these classes actually do and which different oscillator functions go where thanks 
i didn’t try this exact oscillator yet, but every oscillator needs to know the sampleRate to calculate the frequency, so there must be something of it going to the prepare to play-method. then there must be a function that performs things for each sample. they’d be placed in the processBlock-method, where you’ll make a loop that iterates through all samples of the current buffer and the different channels (mono / stereo etc). there you also replace the current output sample with the output from the oscillator.
Have a look at the tutorials, links here -