From the B&H YouTube Channel:
One of the major differences between a snapshot and a beautifully crafted photo is the lighting. Using only available light limits where and when you can take photos. Adding flash gives you endless creative possibilities no matter where you go or what time of day or night. This lecture will first show you how to use as little as one off-camera Speedlite to control and create stand out photos. Then you’ll learn how to use as many as 3 Speedlites to create studio quality masterpieces.
Full Version of Yes, You Need Flash!: https://youtu.be/W2S6A807pEQ
B&H carries photography lighting equipment.