Send your first tracked email.
Compose in Gmail like you always do — tracking is added on Send, with a per-email toggle.
There's nothing new to learn: write your email in Gmail and hit Send. With the extension on, an invisible tracking pixel is added when you press Send. No footer, no visible branding.
Open a new compose window in Gmail. Notice the green Tracking on label next to the Send button. If it reads Sign in to track (extension 0.7.23 or later), the extension is not linked for this Gmail account yet: click the label and sign in first, or the email goes out without tracking.
Click the label to turn tracking off for just this one message, for example a sensitive personal note. Your default lives in Settings.
Hit Send. The email appears in your dashboard, and in Gmail it gets grey ✓✓: sent, not opened yet.
When your recipient opens it, the open appears in your dashboard timeline, and the ticks in Gmail turn green on the extension's next check, within about half a minute.
Want to try it? Send an email to the exact address you are signed in with, wait about 10 seconds, then open it. The tick in Gmail turns green in about half a minute. Use the exact address, not a +alias. If the tick stays grey, send the test to a second address or a friend instead.
Replies and forwards are tracked too — each message in a thread gets its own status, so a fresh unopened reply shows grey even if the original was opened.