Don't be embarrassed. When I first started downloading skins and such I didn't understand Winzip either. I hope this will help you with your problems.
Once you've downloaded a roof, skin, wall, floor, roof, house, whatever what do you do with it? You can't just click the X at the top of Winzip to close it and it just appears in your game. You have to extract it.
To extract a file:
1. Download the file you want to use. Let's use the coral dress for this example.
2. Click on its picture. A window will appear that asks you where you want to download it to. Click open from current location. Then click OK.
3. Then you wait for it to download. This usually doesn't take very long. Most downloads from us besides houses are less than 75 Kb and houses are usually less than 500 Kb.
4. Then a window similar to this appears. Click I Agree or if you have the registered version skip this step.
5. Then this window appears. Now you are in Winzip.
6. Always read the Readme file since it may give you special instructions on what to do. You do this by double-clicking in Readme.txt or whatever I have named it. It is usually the only text file in the zip. Once you have read it you may delete it by right-clicking on it then left-clicking on delete. Then click OK.
7. Now highlight the files you need in your game. That would be the bmp, cmx and skn files. WLL's and FLR's for floors and walls. IFF's for houses. Bmp's for skins, roofs, and customized objects.
Then click Extract.
8. Then this screen appears asking you where to place these files. Walls go in the The Sims\GameData\Walls folder, Floors in the The Sims\GameData\Floors folder, Skins and customized objects go in the The Sims\GameData\Skins folder along with their cmx and skn files, Roofs go in the The Sims\GameData\Roofs folder, and Houses go in the The Sims\UserData\Houses folder
9. Use the + signs to navigate through where to place the files.
10. Then Click Extract.
I hope this page has helped you better understand Winzip. If it has not, please e-mail me at email@example.com and I should be able to help you. Now, back to where you were.