Add Installation instructions (GH-42)

index.md

@@ -1,6 +1,6 @@
 ---
 title: User Manual
-edited: 3 June 2018
+edited: 17 October 2018
 redirect_from:
   - /
   - /Home
@@ -12,6 +12,9 @@ redirect_from:
 
 ## Contents
 
+[Installation](installation.md){: .subpage}
+Instructions to download and install OpenOrienteering.
+
 [Main window](main_window.md){: .subpage}
 Explanation of the main drawing window.
 
@@ -68,4 +71,3 @@ Submit feedback, bug reports, feature requests, and contributions.
 
 [Releases](https://github.com/OpenOrienteering/mapper/releases)
 Releases, with links to change information and known issues.
-

installation.md

@@ -0,0 +1,36 @@
+---
+title: Installation
+authors:
+  - Fraser Mills
+edited: 17 October 2018
+---
+
+OpenOrienteering Mapper runs on Android, Windows, Mac OS X and Linux.
+
+For Android, macOS and Windows, download the latest release from <https://github.com/OpenOrienteering/mapper/releases/latest>
+
+## Windows
+
+All modern Windows computers should be able to run the 64 bit version of OpenOrienteering Mapper so download the file ending with Windows-x64.exe and run it. Follow along with the prompts to complete installation.
+
+The Windows-x64.zip file can be used for portable installations. For example you can transfer the software on a USB stick.
+
+
+## Android
+
+Install either Android-armeabi-v7a.apk or Android-x86.apk depending on your device's CPU type.
+
+If you are unsure of your CPU type follow these instructions:
+
+<https://android.gadgethacks.com/how-to/android-basics-see-what-kind-processor-you-have-arm-arm64-x86-0168051/>
+
+
+## Mac OS X
+
+Download the macOS.dmg file.
+
+
+## Linux
+
+Linux packages for major distribution are provided at
+<https://software.opensuse.org/download.html?project=home%3Adg0yt&package=openorienteering-mapper>.