Beatie if you have bred practically all other livebearers before as you have claimed in other posts, swortails aern't realy any different from mollys, guppys and platys and its realy just a matter of getting 3 females and a male in an adequete sized tank for them, making sure water quality and the swordtails diet is good and making sure the tank has lots of planting for the swordtails to hide in.
You just then sit back and let the swordtails do their own thing and you should have some fry within 2 to 3months, don't buy pre-pregnated females if you can help it though as this causes much stress for them and drastically increases the chances of them having birthing or fry complications etc.