Most CowboyStudio gear isn't worth the money. It's mainly just CPOS gear that has little durability.
StudioHut 4 channel Wireless Radio Hot Shoe Flash Trigger Kit for Canon EOS, Nikon, Olympus & Pentax Flashes with 2 Receivers
Strobist Umbrella Holder with Hot Shoe Mount
Westcott 750 Photo Basics 7.0-Foot Light Stand
43" Collapsible Optical White Satin Umbrella with Removable Black Cover
Harsh light is a characteristic of a small light source, be it on, or off the camera. Hot shoe mounted flash units do little better than the built-in flash does if the light from the hot shoe mounted flash is not modified.
Photographers use light modifiers like bouncing a hot shoe flash, or OCF (off camera flash) and umbrellas to make small light sources seem much, much larger so they produce softer light, and diffuse shadow edges.
Using the flash in manual mode, the lens aperture controls the exposure of the strobed light (flash) and the shutter speed controls the exposure of the ambient light.
The in-the-camera light meter essentially become useless.
When using a wide lens aperture that gives a shallow DoF, less flash exposure is needed for fill. If you're making a portrait of just 1 person 1/8 power may be enough.
As lens aperture gets smaller, flash power has to be increased to give the same exposure, assuming the same subject and subject distance.
Nikon's Auto FP sync mode may need to be used to get a quick enough shutter speed to get the ambient light exposure where you want it. IIRC the built-in flash is not Auto-FP sync capable.
Auto-FP sync introduces it's own problems. Most noteable is that flash power gets seriously reduced since the flash has to fire many times during a single exposure.
Using flash adds a level of complexity to doing photography, and haveing a good understanding of how the camera works is very, very handy.