If it is like my 1997 Caravan, look at the oil dipstick. If you go straight down from there, and look underneath, you will find it. It is a challenge to take out as you need a 15mm box wrench as well as a closed wrench, due to odd placements of the bolts holding it in place. Once the bolts are off though, it comes out easy.
Just replacing mine tonight: look right under the front center of the engine - it's above the engine mount. There's a clip (pita to take off - spray carb cleaner on it to remove grease first) that you have to take of - slide the red clip back. Then remove the nut to the solenoid wire. That's as far as I've got tonight (started raining, and my garage is full). Looks like there's two bolts on the other side of the transmission that go through the transmission housing and into the starter to hold starter & solenoid on the case. Mine's a '99 Grand Caravan 3.3L V6.
It is built in to the starter itself
The starter solenoid on a Dodge Dakota is built on the starter.
Your kit should include instructions.
2 or 3, depends on engine.
Dodge doesn't use inertia switches.
On the side of the engine at the bottom.
These are typically located at the top of the transmission output.
A 1999 Dodge Caravan does not have a cabin filter.
It is on the front of the engine, under the intake.