hey, first off what you have to do for flowy single track is find a good spot for a bit of downhill. this should probably be the start of the track if you dont want to many uphills, get a good rake and start to clear out logs and leaves and the single track should start to take shape, make sure you put in a lot of turns which later on you can turn into small berms and maybe the occasional large berm. when all of the clearing out for the track is done start to build some obsticles. to gain speed at the start build a berm early on and then build some small doubles. hope this can help with your track, good luck