If you see a message on your screen telling you to go to DisneyPlus.com/Begin, all you need to do is the following steps:

Firstly, make sure that you have an active internet connection.
Open your web browser and type the web address, disneyplus.com login/begin. You can also opt for disneyplus.com/begin.
Now, a page will open up. Locate and navigate to Sign-Up.
Now click on the Sign-Up button.
A form will open up which you have to fill up. Write down the name, password and email address. Click on the ‘Next button.
Enter the 8-digit code you see on your TV.
Click the Continue button.
Head back to your preferred device and enjoy Disney plus.