Great addon IDK why people don't know how to use it. Just click on the addon button and then click on a flag. There is no registration required or anything.
Which part are you having trouble with? We need more info to help you. We have tons of people using it without issues. If you have multiple extensions installed, one of them might be the issue. Please let us know.
Sorry you had trouble. Please let me know what you encountered. Something on your end must be interfering as the extensions is working perfectly. Thanks