After you've installed Visual Studio, there are some steps you can take to make it easier to work with C++ code in Unreal. These steps are not at all necessary, and can be safely skipped.
On the right-hand side of the toolbar is a drop-down arrow, as shown in the following screenshot:
Click on this button, hover over the Add or Remove buttons, and click on Solution Platforms to add the menu to the toolbar.
The Solution Platforms drop-down list allows you to switch the project between target platforms (for instance, Windows, Mac, and so on).