Once you have generate a hardware ID and submitted it to Clearly IP support team we will send you back a License File in the support ticket. You will need to follow this wiki to upload your license file in FreePBX.
Copy the contents of the license file the support team sent you.
SSH to your PBX and issue the following commands.
mkdir /etc/clearlyip/
cd /etc/clearlyip/
nano codex.lic
Press Ctrl V to paste in the content
Press Ctrl X to save the file and press Y to confirm and press your Enter key