I will be blunt—using the standard AMD backplate is perfectly fine but the mounting hardware used on the Aquarius 360 AIO hooks onto the plastic AM4 brackets. The solution is inelegant and typically offers a worse contact area than mounting solutions that actively attach to the backplate and all four points. While the solution goes together pretty easily, it took a couple of tries to get an adequate spread of thermal paste. Regardless, the first thing to do is attach the brackets to the pump with the four black screws. Then, with the brackets in place, use the thumbscrews to hold the actual clips to the mounting brackets. Make sure to leave them loose or you will be struggling in the later steps.
At this point, apply the provided thermal paste or use your own preferred paste if you have one. Then position the cooler on the CPU and slide the clips over the plastic AMD brackets. Once they are in place, tighten them down but be gentle and alternate between sides to get even pressure for best performance.
With the pump now secure, I attached the radiator to the chassis and installed the fans. I am happy to see AQIRYS provided extra fan screws should you want to do a push-pull setup. While unlikely, it's still nice to see for the fraction of people who prefer that route, although with no easily found fan model number, you might be replacing all the fans for a matching set considering the performance the cooler offers. That might be the best bet anyway, but more on that later. Finally, with the hardware installed, all that remains is to plug everything in.
Overall, the installation was pretty straightforward on AMD; while not the best mounting solution, it worked just fine. However, on the Intel front, things are a bit different. While it wasn't difficult to install the cooler, AQIRYS chose not to use standoffs to secure the backplate. Instead, you get a sticky foam spacer, and the proper bolts slide through the mounting arms and screw directly into the backplate. This means you have to make sure the backplate doesn't shift while holding the pump in place, sliding the screws through the brackets, and tightening them into said backplate. While it may cost more, standoffs would have been the better choice, making for an easier installation on the Intel test bench.