Access anywhere: As long as you are signed in to Chrome, click the App launcher button found in the upper right corner on any Google page, then click the Gmail icon, or simply go to mail.google.com in any web browser.
Compose and find recipients: Click then start typing the persons name you want to send to.
Reply: In the upper right corner of any email you receive click to reply.
Quick Settings: In the upper right corner click to find options to change your Inbox appearance like Density, Inbox Type, Reading Pane and Conversation view.
All Settings: Click to find options to set your signature, turn your vacation responder on or off, configure rules, labels and more.
Organize: Applying labels is Gmails version of folders. However you can apply multiple labels to a message so you can organize just how you'd like. If you are new to labels, check out this Help Article from Google.
Search: Use the search bar at the top to find emails, Chat messages, or people.