Visual-Studio-2015 is an IDE developed by Microsoft.
It has a user-friendly interface and it is easy to work with, it also support Git repository for managing projects and Xamarin Studio(Mono Develop) to develop android soft wares.
It mostly supports C# , VB(Visual Basics) , F# and C++ programming languages but it also supports other languages like Python or Ruby.
You can get the download link for the setup file in here : https://www.visualstudio.com [Scroll to the bottom of the page and download the Visual Studio]
The setups are relatively simply and common. But do take note when they ask you to download the default or custom, you can choose to download the custom and pick whichever programming language you want to download alongside with it too! [Default mainly comes with C#/VB]
For android/Cross-OS development, you can take Xamarin, it is supported by Visual Studio and vice versa.
When you startup Visual Studio, you can go to the top bar, tools>options and configure how your IDE looks, shortcut keys etc. (Refer to picture below)
And that its , you can basically go to the top bar, files>new to create a new project and start your work!
You can navigate to your desired classes, functions, structures, etc using the top navigation bar here.
Simply click on it, a drop-down list will popup. Click on the desired variable you want to edit, and it will automatically bring to that block of code.
Alternatively, you can also use the Solution Explorer to help you navigate around your codes. It is at the right-hand side as a panel by default. Expand the namespace, classes, and double-click on the desired variable you want to edit, and it will automatically bring you to that block of code.