How to calculate bolt bands from an array in php

Question

I want to calculate the bowler bands using php with my dataset.

I tried using trader_bbands here , but I do not understand the parameter that I have to add, in particular $nbDevUp, $nbDecDnand $mAType. Then I wondered how to calculate it manually using php, perhaps using a queue to calculate the middle band or something else?

Can someone help me understand trader_bbands? I found this one , but it asks about the return value not its parameter.