how to add 'login' button

Hello
How can I add this login button and login area on my website, like in demo?

You need to publish "Login" type module in "Login" position

Thank you, in my opinion Your Company should add this to teh module position http://demo.gavick.com/joomla25/creativ ... -positions it will be much easier to find, where the 'login module' should be.

Could you tell me how can I change those words: "log in or sign up"?

It is clearly described in the documentation:
https://www.gavick.com/documentation/jo ... on-joomla/

If it goes to a translation - template has it's translate file in languages folder - you will find those words and much more that you might like to translate.