Bắt đầu quá trình kích hoạt đối với điện thoại mới (nếu có). Lắp thẻ SIM rồi mở nguồn điện thoại. Liên hệ với phía nhà mạng nếu bạn không thể kết nối.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
If you're setting up a new smartphone, you'll be taken through the initial setup process. During this process, your SIM will typically be activated for your new phone automatically.  See Use an Android Phone for instructions on getting started with your Android device. See Activate an iPhone for instructions on activating your iPhone during the initial setup. If your phone was already set up, you'll usually get service a few moments after you insert your SIM card. Just insert the SIM card, power