Go to daum.net and click 회원가입 (Sign Up).
You have the option to register and verify an account using your Kakao account or with your mobile phone.
Click the second blue button to register your account using your mobile phone.
Click the check boxes to accept the usual terms and click the blue button to go to the next step.
On the next page, fill in your information. After inputting your mobile number, click the 인증 button to send a verification code to your phone. Input the code in the next field and click the 확인 button to confirm. Once you’re done, click the blue button to proceed.
After that, your registration is complete!