Fx help for oscillators

Hello everyone in the community, I had a question following the juce tutorial, in the synthesizer that I am making, I wanted to start adding fx such as delay reverb, phaser, and chorus, I know that these will require a circular buffer, but in my processBlock for the AudioProcessor, I have my synth renderNextBlock taking the current buffer, if I wanted to process a delay effect would I make my synth renderNextBlock again, this time taking the new delay buffer? Also if someone could point me in the direction of creating these effects for a oscillator specifically that would be great.

Thanks a bunch!