I need help understanding?

It's simple. You said you have the e-mail address. Suppose it is abc@yahoo.com. Now "abc" becomes your Yahoo! ID, and "abc@yahoo.com" is your e-mail address. First understand the difference. You need only the ID to chat, not the e-mail address. Ok?

Now, after signing in Yahoo! Messenger, there are 4 options in the menu bar at the top. Click Actions--->Send an instant message--->Other contact. A box will come prompting you to enter the ID of the person. Enter it, click ok.

Now a chat screen will come where you can type and exchange messages. If your friend isn't online, he/she will recieve the messages you send when he/she comes online. You might also want to add your friend in your list, so that you can communicate easily. In the box where you're chatting, check the options above in the menu bar click Actions--->Contact options--->Add to messenger list.

If you click on some ones profile, you will see a little box that says e-mail.

You can then send a message, I am not sure I have understood your question and this only applies to YA, regards Keith.

PS if not on YA. If you have their address, message should go through?

Hello

Click on the mail icon. This will take you to a new screen. On the new screen you should see some choices one of which is addresses. Click on this, if it trells you that you have none click add. Then after you put in info click save add another or save and finish.

Check this link: http://help.yahoo.com/help/us/tutorials/cg/mail/cg... where everything is explained in detail.