Add more instructions to README

README.md

@@ -9,11 +9,13 @@ Self-contained [NodeMCU](https://github.com/nodemcu/nodemcu-firmware) flasher wi
 
 ![Image of NodeMCU PyFlasher GUI](images/gui.png)
 
+## Installation
+NodeMCU PyFlasher doesn't have to be installed, just double-click it and it'll start. Check the [releases section](https://github.com/marcelstoer/nodemcu-pyflasher/releases) for downloads for your platform. For every release there's at least a .exe file for Windows.
+
 ## Status
-Check the [releases section](https://github.com/marcelstoer/nodemcu-pyflasher/releases) for progress and downloadable binaries for your platform.
 Scan the [list of open issues](https://github.com/marcelstoer/nodemcu-pyflasher/issues) for bugs and pending features.
 
-- Due to [pyinstaller/pyinstaller#2355](https://github.com/pyinstaller/pyinstaller/issues/2355) I can't provide an app bundle for macOS yet. The PyInstaller `.spec` file and the build script are ready, though.
+- Due to [pyinstaller/pyinstaller#2355](https://github.com/pyinstaller/pyinstaller/issues/2355) I can't provide an app bundle for macOS yet. The PyInstaller `.spec` file and the build script are ready, though. Of course you can still *run* the application on macOS. Clone this repo and then do `python nodemcu-pyflasher.py` (see "[Build it yourself](#build-it-yourself)" for pre-requisits).
 
 **Note** 
 
@@ -27,6 +29,13 @@ All open-source development by the author is donationware. Show your love and su
 
 [![PayPal Donations](./images/paypal-256.png)](https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=HFN4ZMET5XS2Q)
 
+## Build it yourself
+If you want to build this application yourself you need to:
+
+- Install Python
+- Install [wxPython 3.x](https://sourceforge.net/projects/wxpython/files/wxPython/) (not 4.0 betas!)
+- Install [esptool.py](https://github.com/espressif/esptool#easy-installation) which brings pySerial or install pySerial standalone
+
 ## Why this project exists
 
 ### Motivation