To install Tinderbox, download the disk image (DMG) and double-click it to mount the image. Drag the application icon to your Applications folder (normally shown as an item in your Finder's sidebar).
Open the Applications folder, find the Tinderbox icon and double-click it to open Tinderbox.
For users with more specialist needs or those just wishing to test a new version before over-writing their existing version, Tinderbox can be installed pretty much anywhere (for which your account has permissions).
