I have a Vicks V3100 and dont know how to put it together or if I even have a filter. I do not know what the filter looks like

There is a Wicking Filter that is also the same media that creates the humidity. This filter looks like rolled up paper media(like for a swamp cooler). This filter installs at the back of the unit with the water resevoir removed. The water then is absorbed by this media and as the air passes through it humidity is released into the air. The Wicking Filter will need to be replaced when the performance of the unit decreases and the material becomes hard from mineral deposits. There is also a Protec Cleaning Cartridge that looks like a small plastic ball with a stem on it. Inside this cartridge are softening agents that remove hard minerals and extend the life of the Wicking Filter. The Cleaning Cartridge is just simply placed inside the water resevoir. To prolong the life of the Wicking Filter and unit make sure to use clean and cool water. Distilled water will work the best if available. The harder the water you use the more the unit will need cleaning due to hard water. When the unit becomes clogged with diposits you will need to run a solution of vinegar and water through the unit to clean it. If you use distilled or filtered water(reverse osmosis) then the unit will rarely need cleaning.