How do I switch the build settings in (5.6) to android?

I am new user and interested in developing an android game. I have downloaded the JDK and SDK for the android. The issue that I am running into is switching over the build settings and currently am stuck with PC, Mac & Linux Standalone. Also my android support is blocked from unity.exe.

It sounds like you didn’t install Android support when you installed Unity. You can add support for additional platforms by downloading them and running the installers from https://unity3d.com/unity/whats-new/unity-5.6.0

Once the platform support is installed you’ll want to run through the Getting Started tutorial to let Unity know about all the correct install paths and what versions to support: https://docs.unity3d.com/Manual/android-GettingStarted.html