1. Install Homebrew: http://www.howtogeek.com/211541/homebrew-for-os-x-easily-installs-desktop-apps-and-terminal-utilities/
2. Install dependencies:
   1. brew install boost --with-python
   2. brew install boost-python ffmpeg xerces-c mono
   3. sudo brew cask install java
3. If you have not already done so, unzip the Malmo zip to some location (e.g. your home folder).
4. Add export MALMO_XSD_PATH=~/MalmoPlatform/Schemas (or your Schemas location) to your ~/.bashrc and do source ~/.bashrc
5. When you update Malmo you will need to update the MALMO_XSD_PATH too.

Notes:

These instructions were tested on MacOSX 10.11 (El Capitan).

On MacOSX we currently only support the system python, so please use /usr/bin/python for running agents, if it is not already the default.