I have a 2000 model 4jx1
Turn the switch on and leave it on.
It is a quick warm up button but it is also automatic.
It is designed to come on at temperatures below 15deg.
It will automatically switch off when engine warms sufficiently. If the outside ambient temp is above 15 then it wont engage the system at all.
Start the engine after the glow plug light goes out as you would for most diesels.
5w 30 oil or lower is needed in cold climates like you describe.
When you say wont start does this mean wont turn over at all or turns over but wont fire?