Launch the app and sign in with your Adobe ID.

Ironically, the "x86x64" in the filename is correct. InDesign 2015 was the transition period where 32-bit (x86) and 64-bit (x64) versions existed. However, a legitimate copy from Adobe would never mix both architectures into one "RAR" file.

Intel® Pentium® 4 or AMD Athlon® 64 processor.

Enabled syncing of assets across different Creative Cloud applications like Photoshop and Illustrator.