README.md: fleshed out doc

README.md

@@ -1,2 +1,53 @@
 # qt5-qml-cpp-cmake-helloworld
-Simple hello world example using qt5, cml, c++, cmake
+Simple hello world example using qt5, qml, c++, cmake
+
+## Table of Contents
+
+* [Background](#background)
+* [Build Instructions](#buildinstructions)
+* [hw.qml](#hw.qml)
+* [main.cpp](#main.cpp)
+* [CMakeLists.txt](#cmakelists.txt)
+
+
+## Background
+This is a simple helloworld example: 
+
+* opens up a window an displays the text "Hello world!"
+* The window and text are configured through a qt5 qml file.
+* a simple C++ main is used to start things up
+* cmake is used to configure the build
+
+I spent a number of hours searching for something like this.  An example that showed the barebones of what was needed to have C++ make use of a qt5 qml file.  But most of the examples presumed the use of **gmake** (which is the primary build system for Qt).  For my need, I wanted to see how to things needed to be set up for **cmake**.
+
+As I didn't find what I was looking for, I ended up writing this example from bits of info I could find.
+
+## Build Instructions
+1. mkdir build
+2. cd build
+3. cmake ..
+4. make
+5. run qmlApp
+
+For osx (macOS) users for step 3 you may need something like:
+
+```
+cmake .. -DCMAKE_PREFIX_PATH="$(brew --prefix qt5 )" 
+```
+
+## hw.qml
+`qml/hw.qml` is a simple qml file that creates a rectangle and displays the text "Hello world!".
+
+## main.cpp
+`main.cpp` sets up Qt5 and opens up the `hw.qml` to have the GUI display.
+
+## CMakeLists.txt
+This is the **cmake** config file.
+
+Of note: 
+
+* it looks for the appropriate Qt5 packages
+   * `find_packages`
+* what libraries to link with 
+   * `target_link_libraries` 
+* copy the `qml` directory locally