Ahhh. I see. Well, in short, do this:
1. Put the XT1 shutter speed at that 180 marking, which is your max shutter speed that will sync with a flash.
---- This means anything faster and the timing won't line up, and you'll get a partially-lit exposure that looks wonky.
---- Fun side fact: The X100 series, which has a leaf shutter, will sync at 1/4000th! Neat stuff.
2. Put your ISO at something sensible for the lighting, like 400 outside, or maybe 1600 inside.
3. Now manually adjust your aperture setting wider and wider until the BACKGROUND is exposed the way you want it.
4. Set the flash for 1/2 power and (assuming you're shooting from the hot shoe here) zoom the head to match whatever lens mm you're using. The Yonguos will go from 28mm to 105mm, I think? Remember those are "full frame" millimeters on the flash and you're shooting asmaller APSC sensor, so take your lens length (ex: 23mm f1.4 prime lens = 23 millimeters long) and multiply that lens length by 1.5. Your 23 prime is a 35 in FF terms. Set your flash zoom to 35mm. That focuses the light as wide as your lens will capture, instead of spilling light outside the frame and wasting it.
5. Fire off a shot. Your background will look the same as before you turned the flash on, assuming it's not super close to you (so the flash light isn't really hitting it enough to matter), but your subject is now being sprayed with light. Too much? Turn the flash power down. Not enough? Go to full power. Still not enough? Open up your aperture first, then your ISO.
---- Note: slowing your shutter down here will NOT help the flash brighten your subject. The duration of the actual burst of flash light is in milliseconds, so the 1/180th of a second your shutter was open already grabbed ALL the flash light that there was to grab. Staying open longer won't make the flash any brighter. But the aperture and ISO can make that flash light have more of an effect on your sensor. Aperture doesn't give you grain, so I say do that first, then ISO if you must.
And then you pretty much cruise around taking your shots. When your subject gets closer to you, you'll want to adjust the flash down, so you don't burn them out.