Please follow the below steps to read EPUB Edition and PDF/A eBooks secured by Adobe DRM on your reading systems.

Step 1 - Creating an Adobe ID You must have an Adobe ID <https://goo.gl/Cn9U6P>.
Step 2 - Install and Authorize Adobe Digital Editions using Adobe ID You should have the Adobe Digital Editions reading software <http://www.adobe.com/products/digital-editions/download.html> installed on your PC/ Mac/ or a supported reading device and also authorize your Adobe Digital Editions software using the Adobe ID. Both EPUB and PDF/A formats of eBooks can be read using Adobe Digital Editions.
Step 3 - Reading eBook on Adobe Digital Edition If the above steps have been taken, then downloading an eBook is fun. Please click on the "URLLink.acsm" file and it will automatically launch the Adobe Digital Editions on your device and download eBook swiftly.