Summarize this article:

You can sign up for Netflix on any device, but you'll find that the quickest way to create an account is to use a computer with a keyboard. You can also use the Netflix website from your mobile browser. If you want to create an account from a device such as a Smart TV, click the Free Trial or Sign Up button on the Netflix login screen and follow the prompts. The process will be largely the same as the one described below. Note that this offer may vary depending on your country. If you want to watch HD video, you'll need to select the Standard or Premium plan. The Standard plan allows two different devices to be playing Netflix at once, and the Premium plan allows four devices.  You'll use this email address to sign into Netflix. Make sure that the password is unique to Netflix.  You'll need to enter a payment method to proceed, but you won't be charged until after the trial period ends. If you have a Netflix gift card, you can enter the gift card number to use the balance to sign up. The gift card won't be charged until after the trial ends. This will not affect your service and you can still stream to any devices you don't select now.

Summary:
Visit the Netflix website. Click the Join Free for a Month button. Click the plan you want to subscribe to. Click Continue. Enter your email address. Create a password. Click Register. Click the payment method you want to use. Enter your payment details. Click the devices you plan on streaming to.