I subscribe monthly to Creative Cloud my ID is 'email@example.com'
Help please I spent 20 minutes talking to your customer helpline being passed to four operators before finally being directed to the forums and I am not happy.
I believe you need to have subscribed to either the Creative Cloud Complete or Creative Cloud Photography plans, see Photo editor app | Download free Adobe Photoshop Lightroom 5 trial
If you have either of those you simply need to download and install via the Creative Cloud.
If you have subscribed to the creative cloud, then you should be able to install Lightroom through the creative cloud application manager.