打开App Store。 在App Store找到最新版本的OS X页面。 点击“下载”按钮，开始下载升级包。 打开“应用程序”目录，运行新版OS X的安装包。 根据提示安装升级包。 等待安装完成。

Given the above summary, write a detailed text in English for it.
Upgrades to the latest release of OS X are free, and are generally recommended for access to new features and higher security. You can download these upgrades from the App Store on your Mac. This will usually appear at the very top of the "Featured" tab if you aren't currently running that version. If it's not, you'll find it at the top of the "Quick Links" section on the right side of the Featured page. You can also search for the release name. The latest release at the time of this writing is "Catalina." New releases of OS X are quite large, and the download may take several hours to complete. If you don't have a high-speed internet connection, or don't want to exceed your bandwidth cap, you can take your Mac to any Apple Store and upgrade it for free in-store. If the installation didn't begin automatically after downloading, you can run this program that will appear in your Applications directory. This will begin the upgrade process. You'll be taken through a few screens before installation begins, such as the terms and conditions. Most users can simply proceed through these screens without changing any information. The upgrade will not affect any of your personal files or programs. The upgrade process will usually take 20-30 minutes to finish, and your Mac will reboot once it's complete. You should still be able to find all of your files and programs in their original locations after installing the upgrade.