To use Mailtrack on another computer all you'd need to install the Mailtrack extension on that computer. To do so:
1) Open Chrome on the computer concerned, type https://mailtrack.com/ in the address bar then press enter.
2) Click on the Add to Chrome button then click to add the Mailtrack extension to Chrome when prompted to do so.
3) Once you’ve done that, click Continue to Google on the Connect Gmail screen and follow the prompts to activate Mailtrack on your email account.