I recieved an ACSM file (URLLink.acsm) when downloading an eBook, what do I do with it?

The acsm file contains information about the download and the copy protection of your eBook. Open this file using the software Adobe Digital Editions. The software downloads the eBook afterwards and you can read the eBook on the PC or transfer it to a mobile device. Open the file by right-clicking on it and select Open with → Adobe Digital Editions.