Click the wiki link at top for the STAR-Fusion documentation.
To download the software, click the 'Releases' tab and download the 'FULL'-labeled version.
Note, if you're going to clone the code from github, do it recursively like so:
git clone --recursive https://github.com/STAR-Fusion/STAR-Fusion.git