u want the former which says 3/16 on it. put the nut on the pipe and clamp the pipe, the end should stick out the same amount as the depth of the stepped base of the former. tighten the clamp up. then put the former in the pipe end and screw it down until tight. undo the clamp and ur there. this is stage 1 by the way. if u want the dished end, or 'female' end, do stage 1 as stated first, then follow that by using the screw down tool, place the point of it in the end of the pipe and wind it home- u shouldnt have to use a former for this bit, just the winder itself, this will make it dished.
if your joining copper pipe to the standard steel pipe (ie u made a join) then make sure u give the steel end a FEMALE end and union as the male 1s arnt as good, it could leak.use the male on the copper.
bit difficult explainin without showing but hey ho.