Gem4skis

In WavePad, how do I change the Threshold and Duration settings for the Split File at Silences? On my first attempt, on a 4-song album recording, I changed the duration from 0 ms to 10 ms, and WP found no silent zones for splitting. Subsequent attempts did not again present the setting options window. I cannot find any tools to access the Split settings. How can I change the Split settings? I'm new to WavePad, but I find it quite useful.