With the coming of new gravitational wave detectors we need analytic predictions of waveforms at higher precision. One way of modelling gravitational waves from black hole mergers is by using quantum scattering amplitudes, and the state-of-the-art for this method is the one-loop correction. I will go through the method of setting up an expression for the waveform using the KMOC method, building the scattering amplitude at one-loop using the double copy, and removing unwanted states that arise from it. I will also hint at the two-loop result, which is a work in progress.