Hi might be the wrong forum but I am a bit more comfortable in the Idaho forum - move it if you need to

I have the 2000 F250 4x4 with the PSD 7.3,
my concern is trying to get the truck into "4 low". How do I know when 4 low is engaged or if I am doing it wrong.
Is there a different light that comes on in the dash than the "4 high" light?

Thanks for any help or info