In the example, the "predict" variable is the current price plus the predicted price change within the next 3 bars - under the assumption that the recent part of the price curve resembles a polynom.

What you do with this information is up to you. For instance, you could enter a long trade if the predicted price change is above a threshold, and a short trade if it is below a negative threshold. The correlation variable can be used for preventing trades when the correlation is low.

In this forum section some threads before, another user has posted a similar indicator that predicts prices under the assumption that the recent price curve resembles an exponential function.