So, for this mission, you basically have to follow along just as the little thing above the New Kid says. Hold down left click and do not release until you see the prompt to right click.
Once you've held down left click for a certain while (still not releasing yet!), you'll see a prompt to use A/D to "Find the frequency" as Cartman put it. There's no real technique to this, just hit A/D until the waves begin moving high and fast. I forget if you have to release or not, but if the waves are high and somewhat flashing and it doesn't move on to the right click prompt, then release. Otherwise, when it gives the right click prompt, release and instead right click.
Hope this helps! If you have any questions/need clarification, feel free to ask.