True Hairy Dawg, you need Skinstudio (part of Object Desktop) and a good graphics program (Photoshop, Paintshop Pro or similar)...lots of patience and stick - to - it ness!
Skinning takes time - lots of time, so be prepared. You can't just whip one up in an evening!
Object desktop can be found here: https://www.wincustomize.com/store/index.aspx#W011 or you can download the free version of Skinstudio here: https://www.wincustomize.com/software.aspx
I can't recall which features are not available in the free version.
There is a manual available here:
https://www.stardock.com/products/skinstudio/docs.asp
There are some excellent links here:
http://adam.joeuser.com/index.asp?aid=10204
I made recently a set of step by step tutorials that cover both Windowblinds 4 and Windowblinds 5 formats - that are available here: http://skinartistry.com/news.php but you need to sign up to access them in the tutorial section. Signing up is free and there is no other agenda except to help and encourage new skinners and old.
There are a few basic rules that you need to know: do not use someone else's work and call it your own just because you tweaked it or recolored it. If you want to use something you like, ask the owner of that piece of work for permisssion to use it. Under no circumstance assume that getting no reply means it's ok....Maybe the authors e-mail address has changed, or the mail has been lost. If in doubt about an image...ask someone. Most of the skinners here as well as the moderators can point you in the right direction.
I hope this has been of some help.