The first option is !siLagrange - automatically detects the maximums/minimums of the points and creates the polynomial on their basis

The second option is !siLagrangePnt - creates the polynomial based on the points specified by the user. The points are set using the "Arrow" tool.

Make sure their names match the parameter specified in the indicator. For more detailed help, see: https://www.mql5.com/ru/forum/105388