Nutrient film technique is commonly known as NFT in the hydroponic industry and is popular among both commercial and home growers. It's simple design makes it easy to set up and it's perfect for smaller and fast growing plants like lettuce and baby greens.
There's a lot of different ways one can set up a NFT system but the basic method is having a shallow nutrient solution which slowly cascades in a downward direction. This can be done in either larger tubs or commonly within tubes like PVC piping. Once the water has flowed down the tubes (via gravity) it then lands in a reservoir where a submersible pump takes the nutrient solution back to the top / highest point of the system. This process is then repeated on a continuous basis.
Hint: Ensure you use a recirculating nutrient when using a NFT system.