add better download section

README.md

@@ -12,11 +12,17 @@ Perfect for field work on portable touch devices.
 
 Check the [documentation](http://qfield.org/docs)
 
+### Android
+
 [![Get in Google play](http://www.qfield.org/images/Get_it_on_Google_play.png)](https://play.google.com/store/apps/details?id=ch.opengis.qfield)
 
-[Download the latest windows beta version](https://nightly.link/opengisch/QField/workflows/windows/master/QField-dev-Release.zip)
+### Windows (Beta)
+
+[![Download the latest windows beta version](https://qgis.org/en/_static/images/app_download_windows.png)](https://nightly.link/opengisch/QField/workflows/windows/master/QField-dev-Release.zip)
+
+### iOS (Alpha)
 
-[An iOS version is being developed, subscribe to be among the first to test](https://forms.clickup.com/f/22wqj-2878/D6IEV7K3PKVONXPX8P)
+An iOS version is being developed, subscribe [here](https://forms.clickup.com/f/22wqj-2878/D6IEV7K3PKVONXPX8P) to be among the first to test
 
 ## Contribute