when you first start cloneing,i would start of with smaller clones about 3/4 "look for a stem has has a couple of nodes you can take of the plant, but i have took clones of clones and done just fine i take them at around 7/8" now helps in the long run.
Once they have legs they look like little plants to start with,but if you do take them and there is no nodes just use a stanley blade clean one ,clean it with alcohol take it at a 45 dg angle,but don't worrie about that first cut if you are takeing more than one have a jug of water at hand just make sure stems are under water straight after the first cut.
get some clone x put the clones that have been in the water or straight of the plant if you are working with a couple into the clone x dont over do it with clone x,i have just took four with out clone x still root just not has fast,if you take clones with out nodes that have been cut of just peel back about 5 mm,before putting it in the clone x.the reason i say dont worrie about you first cut of the plant is i normaly take a few so i all ways make a fresh 45 dg cut before putting into clone x.
A good tip if these will be your first set of clones is have the full stem in the medium i use rock wool so ruf guess the stem you want it about 5 mm from the bottom of the cube,i only use a proagator for about 4/5 days i only mist twice a day for 2 days during first two days mist the inside of the proagator lid too,with the vents closed.
Then the other 2 days open the vents and mist once a day,the more you mist them the less they have to work to gain water intake through the leaves.after the 4/5 th day the lid comes of the propagator and i only mist say 3 times a week but don't let the cubes dry out you want them damp not wet through.
They will wilt for the first few days,but this is where most new cloners panic.don't just be patient they will straighten up after there first few days,then don't be in a rush for the roots to come through.Has long has there stood up and look ok they will root,it might take 7 days it might take 14/16 days take a few more than you need and slect the first to root has your plants to grow,these have shown that there stronger by rooting first.
Has long has you don;t rush it you will be fine it aint hard dude,i have found they root better with a bit of neglect after the first 5 days just keep your eye on the medium from drying out.
I also use a kebeb skewer to gage the size of stem so i can make a hole in the cube,and you don't push the clone through the bottom of the rock wool bit bigger than the stem then just gently push the rock wool around the stem