The central line is the central line of the price channel.
The line above the center is higher by the average deviation.
The uppermost line is higher by 2 mean deviations.
Similarly for lower lines.
It 's very similar to Bollinger Bands.
Strategy
If the price is above the top line, open the long position (and close the short position)
If the price is below the bottom line, open the short position (and close the long position)