Go to the Gmail "Sign In" page, then enter your login information and click "Sign In."
Gmail Chat is a free service integrated into your Gmail account. Unlike other chat applications, you don't need to download or install any software to access the service. When you activate a chat session in Gmail, the chat window opens in the Gmail account window. However, this is inconvenient if you have more than one window open, because to continue chatting, you must go back to the Gmail account window. Fortunately, Gmail allows you to pop-up the chat session so it is in a window completely separate from the Gmail account window.
Hover your cursor over a contact you want to chat with in the "Chat and SMS" section on the left side of the screen. A pop-up window opens. A person who is available to chat has a green button on the left side of his or her name.
Click the "Chat" button on the pop-up window. The "Gmail Chat" window opens at the lower-right corner of the page.
Click the "Pop-out" button on the window. The button is a small arrow pointing up and to the right at a 45-degree angle. The chat session is now in its own separate window.