Download the latest release (currently 3.2) and untar on your server, make sure the binary has executable permissions then run the binary.
Run the following commands on your Linux server.
cd ~
wget https://github.com/fiorix/freegeoip/releases/download/v3.2/freegeoip-3.2-linux-amd64.tar.gz
tar xvfz freegeoip-3.2-linux-amd64.tar.gz
cd freegeoip-3.2-linux-amd64
chmod +x freegeoip
./freegeoip
Once you've done that, you should see the following:
2017/06/23 14:26:21 freegeoip http server starting on :8080
2017/06/23 14:26:21 database info: starting update
2017/06/23 14:26:22 database info: finished update
2017/06/23 14:26:23 database loaded: /tmp/freegeoip/db.gz
At this point you should be able to visit http://your-server-ip:8080/json/ and the service should be up and running.
Note: The above steps were tested on a Ubuntu 16.04 server. This doesn't install the binary on your server, it only a runs the binary.