Summarize the following:
This is the yellow icon with a white ghost in the middle. Enter your username and password and tap Log in. This will open the Chat window. You can also tap the Chat Bubble icon in the lower left. This looks like a chat bubble with a "+" in the upper right corner. A blue check mark will appear next to the name when selected. A group chat will be created will all of the selected friends as recipients. You can also create groups on the fly when sending snaps by tapping the Add Friends button. This looks like a person with a "+" in the upper right corner when choosing who to send the snap to.
Open Snapchat. Sign in to your account (if necessary). Swipe right. Tap the New Chat button. Tap each friend you want to add to the group. Tap Chat.