You will find here Help Topics.
You can find your clan tag in the Clash of Clans game under my clan. The clan tag starts with #. e.g. #2LQ99UQ2
You can find your clan signatur in your clan profile e.g. here.
For the first login, you have to activate your account. After registration an activation email is sent to you. Please follow the instruction in the email. Somehow, it can happend that the activation email will be in your spam folder and not in your inbox.
This does not help you and you need support? Please use our contact form and place your request there. To the contact form.