How to Chat on Facebook Using Yahoo Messenger for Android

Steps:
1 Download Yahoo Messenger. Simply search for the app in Google Play, tap “Install” button and wait for it to finish downloading and installing.
2 Sign in your Yahoo ID. Enter your Yahoo ID and password then tap “Sign In” to proceed. If you don’t have an ID on Yahoo yet, simply tap the “Sign Up” button and fill all the required information to get one.
3 Open Yahoo Messenger menu. Press your device’s Menu button to open the messenger’s menu.
The location of the Menu button varies depending on your phone model, but most of the time this is the button on the lower left of your screen beside the Home button.
4 Select “Options” from the app menu.
5 Link to Facebook. Scroll down the Options page and tap “Facebook Chat.” Inside this option, tap “Link to Facebook” and a Facebook log in screen should pop up.
6 Enter your Facebook account details (email address and password). Then, tap “Log In.”
7 Accept permission. Yahoo Messenger will ask permission to access your Facebook details, such as your friend list, birthday notification, etc. Tap on “Ok” to proceed.
8 Go back to your Contact list. Your Facebook friends will now appear in your contact list under a group.
(Source: wikiHow)