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It depends on your setup.

The first thing is you need a standpipe with holes in it, the holes should cover a good range of the length of the standpipe for example 12" with as many holes as you can drill in the standpipe over that length. This will give you enough room to adjust the height in the overflow box between the bottom of the holed area of the standpipe and the top. Aim for a water level about the middle of the holed area of the standpipe. Too low and it will suck in air.

The second thing is, if you have two overflow boxes, it will be more tricky, it can still be done but it can take more adjusting to get both overflows flowing silently.

The third thing is, you need a gate valve, not a ball valve.

The fourth thing is, if you have a wavemaker, Tunze wavebox or various powerheads on a timer, this will throw everything off and you may not be able to achieve silent Herbie overflow.