Follow the instructions to step 3. Right-click the patcher and choose Show Package Contents to see the application's contents. Then navigate in /Contents/MacOS/ and there you will find the "mojopatch" file.
Open the terminal (Applications/Utilities/Terminal) and drag and drop the "mojopatch" in there.
At the next step, you navigate to the root of the patcher where you will find the "default.mojopatch" file. You drag and drop it in the terminal too. It should be looking like this one:
/Volumes/UT2004\ for\ Mac\ OS\ X\ 3369.2\ patch/UT2004\ Mac\ OS\ X\ 3369.2\ patch.app/Contents/MacOS/mojopatch /Volumes/UT2004\ for\ Mac\ OS\ X\ 3369.2\ patch/UT2004\ Mac\ OS\ X\ 3369.2\ patch.app/default.mojopatch
Now you push the "Enter" button and the patcher should start.