Bachmann Trains Multi-Accessory Power Supply (16V DC) Grey

Q: How to connect Bachman multi accessory up

Plug in adaptor from multi accessory unit to mains power, connect wires + & - from your accessories to plugs on side marked + & - I have used a 12 outlet hub to take accessory wires that way only needing to wires to connect to multi accessory unit works well for point motors. Sorry can't provide video

Q: My son has a small set with a controller that cannot add switches, withh this work with it?

I have the same kind of setup. Yes it will work

Q: I have right now 4 switches 2 right and 2 left will this run all 4 and i still would have 2 spots left to use if i am correct .??

I run 4 switches now. Since the switches are only momentary contact you could run many more unless you're switching them all at once. I have the power supply wired into a terminal block with 12 connections for lights and switches when I activate the switches the lights don't even blink.