Hello and welcome to the SINE community!
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Isochronic tones are a quite effective method for brainwave entrainment.
A preset contains a noise track and usually 1-2 entrainment tracks.
The noise is a "necessary evil" in these type of stimuli because without it, you will stop hearing the pulses after a while. The noise used by SINE is a filtered pink noise, so it's not too irritating. Usually I prefer to have a mid-high amount of noise (~20-25%) in the intro and outro of a preset, and lower the volume to emphasize frequency changes.
The entrainment tracks is where the magic occurs: they create short pulses of varying frequency (called entrainment frequency, or just beat) by modulating a sine wave (called carrier, this frequency can also change for a more pleasing sound). The entrainment frequency is the most important part: when you focus on these pulses, your brainwaves will tend to synchronize with them, and different frequencies will produce different effects.

These frequencies are usually divided into:
-alpha waves (7.5–12.5 Hz): when you're relaxed, doing nothing, not thinking, but not sleeping either
-beta waves (12.5-30 Hz): this goes from being awake and doing something to active thinking. these frequencies will boost your logic skills
-gamma waves (25-40 Hz): this goes from problem solving to an "intensely awake" state, like when you have too much caffeine
-theta waves (3 - 7.5 Hz): rem sleep, meditation
-delta waves (<3 Hz): deep sleep, deep meditation

Isochronic tones are most effective in the 2-25 Hz range.

Here's a few frequencies (taken from the SINE Editor manual, you might want to try it):

0.5 - 1.5     Pain relief
0.5 - 4     Deep sleep, profund relaxation, meditation
1.2 or 10     Headache relief
3.6 or 6.3     Reduces anger and irritability
4.5 - 6.5     Vivid dreaming, lucid dreaming
5.8     Reduce Fear, absent-mindness and dizziness
6 - 8     Helps long term memory access, past life regression
7.8 - 8     Extrasensorial perception, paranormal
7.83     Schumann resonance. Earth resonance frequency. Believed to have a healing effect
8 - 8.6     Reduces stress
9.8 - 10.6     Alertness
11 - 14     Focusing on something
12 - 14     Improves learning
18     High beta state, improves hyperactive behaviour, studying, etc.
18 - 24     Euphoria
19     Fear
20     Reduces tinnitus temporarily
20.215     Believed to mimic the effects of LSD
30     Believed to mimic the effects of Marijuana
32     Desensitizer

You can find more frequencies around the internet, on sites like this: http://www.electroherbalism.com/Bioelec … cyList.htm

If you're young (<20 years) keep in mind that your brain will not respond to brainwave entrainment like that of an adult (20-25 years at least) because the frequencies are different (usually lower in frequency).
Another thing to know if you're new to brainwave entrainment is that it doesn't always work the first time you try it, and there's a good 10-15% of population who doesn't respond to brainwave entrainment at all. So start with simple presets, like the ones for sleeping, and try them a few times if you don't get immediate results.

I hope my answer was informative enough. If you want to know more, I'm here.