How do I get a password for Acrobat XI Pro?

I am currently using Acrobat XI Pro. I really like the way it works and, I would like to keep using Acrobat XI Pro.

I decided it is time for me to upgrade my Mac Pro to El Capitan. To do this, I installed a second hard drive and put El Capitan on the new hard drive. So, I am doing a clean install of Adobe Creative Cloud on the new hard drive. However, Adobe Creative Cloud wants me to install Acrobat DC. There is an option to download Acrobat XI Pro. However, I am required to give a password. I don’t know how or where my password is. I know I am using a legal copy.

I think I gained access to Acrobat XI Pro through Creative Cloud but, I am not sure. I also own Creative suite 5.5 and 6. However, those passwords don’t seem to work so, Now I don’t know what to do.

(One of the reasons that I need Acrobat XI Pro is because I need a plugin that is not compatible with Acrobat DC yet.)

Please let me know how to install Acrobat XI Pro.

Thank You