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 .
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)
In true TradingView spirit, the author of this script has published it open-source, so traders can understand and verify it. Cheers to the author! You may use it for free, but reuse of this code in a publication is governed by House Rules. You can favorite it to use it on a chart.