docs: update installation instructions

docs/sources/installation/mac.md

@@ -11,6 +11,8 @@ weight = 4
 
 # Installing on Mac
 
+## Install using homebrew
+
 Installation can be done using [homebrew](http://brew.sh/)
 
 Install latest stable:
@@ -75,3 +77,18 @@ If you want to manually install a plugin place it here: `/usr/local/var/lib/graf
 
 The default sqlite database is located at `/usr/local/var/lib/grafana`
 
+## Installing from binary tar file
+
+Download [the latest `.tar.gz` file](https://grafana.com/get) and
+extract it.  This will extract into a folder named after the version you
+downloaded. This folder contains all files required to run Grafana.  There are
+no init scripts or install scripts in this package.
+
+To configure Grafana add a configuration file named `custom.ini` to the
+`conf` folder and override any of the settings defined in
+`conf/defaults.ini`.
+
+Start Grafana by executing `./bin/grafana-server web`. The `grafana-server`
+binary needs the working directory to be the root install directory (where the
+binary and the `public` folder is located).
+