Uncompress the file, install it on the webroot of your server and run it.
Demo video: Install SofaWiki in one minute: install.mp4
The newest version is always on this link
The current version is 3.1.2
Note that the mac may fail to decompress the file after download. You can however decompress it from the Terminal
Now you can proceed to Installation.
Sofawiki is also available with the Softaculous Auto Installer.
For example, if you have CPanel, you can add it from the Softacolous Button in the Software panel.