Buy some distilled water,if your tap water is not that good ,I use tap water my self,cut at a angle just below and side growth be it new growth or leaves (nodes) .
Then into rooting gel I use aloe Vera ,but clone x works,well.Make a hole in the medium a little wider than the stem,then place the clone into the hole,pushing the sides of the medium in round the stem,mist them with a very fine mist just water.
Put in a propagator with the vents closed for 2 days,open the vents on the 3 rd day ,during this time they will wilt,but don't panic they will be ok,mist the inside of the lid,and the clones twice a day for the first 5 days,then after 5 days ,just once a day for about 3 days,after that just ever so often let them work for the water.
It may take 12/14 days to root but they will root,has long had you don't faff around with them and hey will be fine,I use a normal house lamp cfl,with a warm spec bulb in,this helps with warmth,I try and get a blue spec,I use a cool warm spec in summer ,this may sound not needed but if weathers warm I don't like them getting no too hot.
Also don't take them too big the bigger they are the more effort it tak s the plant just to maintain life,smaller is better.i don't ph or add anything other than water,I sometimes have to re soak the cubes in water with aloe Vera in it.