Ros, being a fellow X-T1 user and having dabbled in smoothing running water, I can offer this advice to get as long an exposure (to smooth the water) as possible.
1. Set the ISO to the lowest possible setting (Left hand dial to "L".)
2. Set the aperture on the lens to the smallest aperture possible (slightly confusingly, the highest number on the ring or in the display.)
3. Set the shutter speed dial (Right hand dial, closest to the lens) to "A", like in Matt's posted shot.
4. You already have the exposure compensation dial set to "0".
5. Wait for the light levels to fall enough to allow you a shutter speed (as chosen by the camera, you having basically asked it to give as long an exposure as possible for the available light) of 2 seconds or so. If that doesn't give you enough blur on the water, wait a few more minutes for the light level to drop a bit more.
6. If you have a polarising filter, you can use that as a Neutral Density (ND) filter to reduce the amount of light getting through to the sensor meaning you'll get a longer exposure. You may want to invest in a polariser (you'll need a Circular Polariser rather than the Linear type) anyway since they are possibly the only filter that's all but impossible to replicate in Photoshop or similar. You might also want an ND filter or 2 to extend the exposure in future (loads of threads covering the use and choice of ND filters here!)
Good luck and welcome to TP.
