spi road map, page-124

evening gm207..

the Medianlines are set up at the beginning of the contract.eg: abc..

and then they are carried forward into time..

so there are no setting as such..it is just a easy tool to use and very simple..it is in every charting package i would think..
you will find though they tend to hit on fibonacci nos..amazing stuff..
the medianline has a 80% strike rate..

hope this helps explain it
ac :-)