Tap the Skype app icon, which resembles a white "S" on a blue background. Doing so opens Skype if you're logged in. If you aren't logged in, enter your Skype email address (or username, or phone number) and password when prompted before continuing. When using Skype on Android, you have the option to respond to an incoming call with audio only or with video in addition to audio. If you don't know which option the caller prefers, start with audio. You can always switch to video later. Once the person begins calling you, your Android's screen will change to display the name of the caller at the top of the screen and answering options at the bottom of the screen. It's the white phone icon on a green background at the bottom of the screen. If you want to respond with video, you can tap the green-and-white video camera-shaped icon at the bottom of the screen. It may take a few seconds before you can hear (or see) the caller.
Open Skype. Determine whether you want to answer with video. Wait for the Skype call to come in. Tap the "Audio" icon. Allow the call to connect.