i love the top photo
the bottom is still a bit harsh lighting wise but is a cute setup heavens you have wonderful models :)
if you need your on camera flash to trigger your strobe, you can compensate by going to the flash exposure comp in your menu and by test shooting adjust there
off BUT you can do it with it on too...
turn it down so its not so harsh, and you can also put a tissue over it to baffle it like the front of the softbox does to your light
if I was to use my softbox and find a light for back would i want my camera flash on or off
You pick.
There is no right way to light. But, there are plenty of wrong ways.
You could use your flash as the key. But, know this...your flash is daylight balanced, or 5500 Kelvin. Your studio light is probly tungsten based, it is 3200 Kelvin.
Not that this is a bad thing, we do live in an imperfect world. However, critiques here at DPC may say something.
You can put jell on either/or to help balance the color temperature, or just go for it.
Here are some single points lighting set ups.
Here are some multi point lighting set ups.
Experiment. Look around. Improvise.
Remember too, Home Depot is the poor mans source for light.
All of my lights are from Home Depot. I got the compact flourescent daylight adjusted ones. I think they're NVision (or something like that). They didn't have them at Lowe's. I just use them in the clamp light shells and, if I need to, I drape something over it to diffuse the light (usually fabric made to line clothing with, it's sturdier but still thin).