To put simply, the LW company is no longer; the LW company is closed. Their site is no longer use-able. Their skins download page was withdrawn from their site. So to find skins, we need to find custom ones made by other persons. These ones are not possible to install directly into LW. Firstly they are zip. The .zip needs to be changed to .lwtp then added to the skins folder within the LW program folder. Then they should show up in the skins menu next time LW is opened. It seems this is the only way to do it. And was always the only way to apply 'custom-made' skins.
Once you have succeeded with doing this once, you will see it was not too complicated. But it's not easy to explain the process all the same.
We provide links to older LW versions on this forum, we also still have custom-made skins that are still available.
I will discuss this issue with File_Girl to see if she can design a program that will do this entire process, so people do not need to go through the manual steps. Probably something like: will change the zip to lwtp then move or copy to the LW skins folder inside the preferences folder.