I took some time to find this page...

If you had made your account and logged in, then the front page turned to be "How to get started" page with only the link to Chrome extension.

If you want to use Firefox bookmarklet, you do as follows: 1) If you had logged in, sign out 2) click GET STARTED button 3) find the link to "other browsers" in the line with number ➁

I think it's misleading. The better way for me to put the link to "other browsers" in the "How to get started" page for the users who already logged in. Thank you!