hehe okay I used to use corel once upon a time but i can't remember how it works and my version is a million years old but here is one step to start with
you have to learn how the lines on the templates work on your avatar so import the templates and put them on and look at the lines (I made a 10x10 white box in the sky and stood there with templates on for a long time and worked on my software with a second set of the templates just to try to figure it out
open up the templates inside corel draw you will have to loose all the layers he uses layers as his files are for photoshop also you will probably in the long run need some sort of photo editing software as well for this you can download gimp and also look for the slcp program this is good to see how the clothes look outside of second life but its not exact I find what bends in some areas on the SLCP program doesn't bend the same way in second life, but its very very close.
since you can draw just draw a simple item like say a shirt and pants very plain on the templates you open up inside corel draw. Save the templates first as you will need to use them over and over and over again that will be the base for every single piece of clothing you make for SL.
I would just start with just colouring in areas and make a solid coloured shirt and pants no real patterns or wrinkles etc so you can understand how it all works
then once you have drawn your simple items you have to get them from your computer to SL so you have to convert them to TGA format again I can't remember what corel draws capabilities are but if there is no way to convert to TGA you can do this in gimp which is free
after that you will have to learn a bit about alpha layers but for now figure that out if you have never done it before and have trouble learning that is enough "homework" to keep you busy for a few days

gimp is
www.gimp.org i think
errm SLCP its in the top set of links on the top sorry hehe have to look it up myself its a program which you run on your computer as well.
if corel wont make tga files save your corel file the gimp can convert corel formats I have seen it there. open the GIMP and open up the corel file you just saved and click the save as button and select save as tga 32 bit and no RLE compression
also i'm not sure how much else it can be explained as all that i have just said is explained better in the links above hehe basically you just start at the top of the links and work your way through
for now you need to learn how to draw onto the template
save as a tga file
import those files into the game
edit them in appearance
hope that helps you should find the links pretty easy from the information I just gave you
