Login to your Yahoo Messenger by typing your Yahoo id and password
The main window will appear on your screen from the tabs shown above click Preferences.
From the drop down menu select Messages.
A new window will open on your screen on which you will have to enable the use of emoticons by choosing Enable Emoticons.
Hit the Apply button
Next you will have to move the downloaded emoticons to Yahoo Messenger’s emoticon folder.
Then you will have to copy paste all the wp-content/uploads to the path where Yahoo Messenger is installed if it is in the C drive then the address should be "C:\Program Files\Yahoo!\Messenger\Media\Smileys."
To copy paste the wp-content/uploads press Ctrl key and highlight the relevant wp-content/uploads, then press Ctrl + C and paste them in the destination folder by pressing Ctrl + V keys together.
Now again log in to your yahoo Messenger and open a conversation window of any of your contact. Click the Emoticon icon and you will see the new installed emoticons in the list. Make sure the installed icons are named correctly so that you can press the accurate keys to use them.