I want to connect an electrical device that runs on 12V or less voltage.
Where can I connect it from below the dashboard (the lighter doesn't count, unless it has an under the hood part).
Assuming you have spade fuses, you can use one of these [spade fuse taps](fuse spade tap) to get your power:
It fits over the blade on the fuse, then you push the fuse down into its normal position in the fuse panel. You can connect the other end to a grounding point. To find one look for a metal nut or a bolt in the vicinity of your fuse panel.
When you do connect it, ensure you do two things. First, make sure you are pulling power from before the fuse and not through the fuse you are using. This will ensure you are not drawing more power than the fuse can handle. Second, use an inline fuse to support your equipment. This will protect the car and the equipment should there be a shorting issue going on.