This Gaussian equation picks a random (actually pseudo-random) number from a Gaussian (normal) distribution. This distribution has a mean of 0.0 and a standard deviation of 1.0.
This equation can be used as an equation inside another equation (what we call at vCalc an EiE) to generate a random number about the mean of 0.0.
To select random values repeatedly, just click the refresh icon to the left of the output field which displays your pick:
If you use the default values and set the number of bins to 10, you will get a distribution that looks like this: