Ignition Switch

My son inserted a key into the ignition of my 1990 Dodge Grand Caravan. It cause the tumblers to fall. I need to know HOW to change the ignition switch

It is quite difficult unless you have the tools. You need two separate pullers. Best advise is to take it to your local garage. You can get a book from your local library, but it's tricky work and could end up costing you more than you bargined for. I wonder why the tumbler came apart. Hopfully it was just plain worn out, and nothing else was forced in there.