Building on the good advice from Will, have you checked the video tutorials on the Lencarta website? You need to learn the basics. There's tons of lighting info around.
For starters, I would use just
one head, with the white umbrella. Leave the other one in the bag for now. Position it just above and to one side of the camera, close to it. That will give you soft light. Use the reflector to fill-in even more if you need it. That's all you need for the main subject - less is usually more with lighting, especially when you're starting out. For solo portraits, only use the second light for the background until you get proficient.
Leave the modelling light on (permanently) and move the flash around to see how things change. Eg closer light means softer light, as the umbrella becomes relatively bigger compared to the subject.
I would use 1/125sec shutter speed (just to be absolutely safe on x-sync) and say f/8, lowest ISO and flash on half power. Check the LCD and histogram for exposure, and enable the highlight over exposure warning in the menu (known as blinkies).
Adjust the exposure with the power setting, and/or the f/number. Leave the ISO at base for best quality, unless you run out of other exposure options (which you won't with these settings).
That will get you going with a simple, attractive and versatile set up for basic portraits. There is lots to learn, but getting on and doing it is a pretty good way. Ask plenty of questions on here and post a couple of pics
I'll just say one more thing. Fancy equipment and advanced techniques all have there place, but that's not what what makes a great portait. Your subject makes a great portrait and so long as the lighting is there or thereabouts, you're first priority is to give them 100% of your attention. Get the best out of them first and worry about the technical stuff second.
