Currently we support only user credentials authentication. So, you should enter web address and user credentials of REDMINE.
Type web address of your Redmine account, your username/email and password.
If you don't have an account, click on Create one! link.
Click on Validate connection to check it.
Choose Save to apply this credential and start first loading. The add-in loading requires data, such as system lists, projects, so this may take some time. Please wait.