First, read the English article below.

If you use iTunes to pay for Netflix, you'll need to adjust your plan settings through iTunes itself instead of the Netflix website. This will open the Sign In window. If you're already signed in, you can skip these steps. Make sure to use the same Apple ID that you use to pay your Netflix bill. This will open your account page in iTunes. You'll be asked to enter your Apple ID password again. This will allow you to make changes to your iTunes subscriptions, including Netflix. You'll be asked to confirm that you want to make the change. Your changes will take effect on your next billing date.  In most regions, you will have three plan options: One Screen in Standard Definition (SD), Two Screens in High Definition (HD), and Four Screens with HD and Ultra HD (UHD). The more expensive plans will provide higher-quality video and allow more people to watch at once. Not all options are available in all regions. Netflix recommends a 3.0 Mbps connection for SD content, a 5.0 Mbps connection for HD content, and a 25 Mbps connection for UHD content. If you began your membership before 5/10/2014, you'll only see the two-screen option. To see all of the available options, you'll need to cancel your subscription and then resubscribe. If you started your account after 5/10/2014, you should see all of the available options. 

Now, please write a short abstract for it in Chinese. Abstract:
在电脑上的打开iTunes。 单击iTunes顶部的“登录”按钮。 输入Apple ID和密码。 单击右上角的头像，然后选择“帐户信息”。 找到“订阅”部分，并单击“管理”。 在“续订选项”部分中选择期望的方案。