Obviously you didn't read the instructions and yet you keep asking... wasting your time and mine.
Please do me a favor and read more carefully before you ask. I've taken the time to provide all the information one may need when downloading a file to save time from such questions.
Anyway, I'll copy/paste the instructions here. Good luck.
Download the skin and follow the steps below to get it into your game:
Copy the folders you extracted into your skins folder this is by default (you may need to create the skins folder if it doesn’t already exist):
Win Vista/7:C:\Users\<username>\Documents\Sports Interactive\Football Manager 2011\skins Win 2000/XP:C:\Documents and Settings\<username>\My Documents\Sports Interactive\Football Manager 2011\skins Win 98/ME:C:\My Documents\Sports Interactive\Football Manager 2011\skins Mac OS X:/Users/<username>/Documents/Sports Interactive/Football Manager 2011/skins
If you cannot find your user data folder:
You can find the location of it from within FM2011, load the game go into the preferences menu and at the bottom will be a section called User Data Folder, this will list the current location and will also allow you to change it or set it back to the default location:
You need to ensure you didn’t add an extra folder to the layout, when you copy the folder for your skin into the skins folder and go into the folder for your skin it should look something like this:
In the above example you will note that within the skins folder is a folder called base2011, and when you open the base2011 folder you see three more folders and a xml file called base2011 – if your skins folder looks like this (with the skin_name.xml file inside one skin_name folder) then you have installed the skin correctly.
To select the skin in game you will need to:
load the game, and go into the preferences -> Display and Sound menu
untick ‘Use Skin Cache’ and tick ‘Always Reload Skin On Confirm’ then select confirm and
select the skin from the drop down menu, select confirm again and your new skin should now display. (Once the skin is loaded you can turn the skin cache back on and untick the Always Reload button.)