Clean 12v switched source that is hot cranking and running

You hook the fused battery power to "batt' just like it says.

You hook the output pin 87 to your igntion/ EFI loads just like it says

You connect 31 to ground just like it says

And you connect 15 to your 'ignition run' and jumpered to "IGN2" just like it says

You set the delay for I'd say less than 1/2 second. There are two switches to set the range and an adjustment pot to adjust the delay within that range.

When you turn the key to "run" it sets the delay and powers the load. When you switch to "start' if there is a glitch between IGN1 and IGN2 the 1/4 second or so delay will keep the relay engaged. When you shut off the key the relay will drop out 1/4 sec or so later depending on where the delay is set.

I would not set this very long. You don't want the engine to not shut off when you turn off the key, as a lot could happen in let's say 1 second.