Step by Step guide to download and install BE 2010 R2: http://www.symantec.com/docs/TECH138264

BE 2010/R2/R3 Administrator's Guide: http://www.symantec.com/docs/DOC2211

BE 2010/R2/R3 Software Compatibility: http://www.symantec.com/docs/TECH137682

BE 2010/R2/R3 Hardware Compatibility: http://www.symantec.com/docs/TECH137050

BE 12.5 Software Compatibility: http://www.symantec.com/docs/TECH62301

BE 12.5 Hardware Compatibility: http://www.symantec.com/docs/TECH62114

BE 12 Software Compatibility: http://www.symantec.com/docs/TECH56442

BE 12 Hardware Compatibility: http://www.symantec.com/docs/TECH55640

How to upgrade and migrate BE 11d/12/12.5 standard,CASO and SAN/SSO environments to 201o with a different server name and version of windows: http://www.symantec.com/docs/TECH137015

Direct upgrade path from BE 11d/12.0/12.5/2010 to BE 2010 R2: http://www.symantec.com/docs/TECH148394

Multi-step upgrade path from BE 10.x to BE 2010 R2: http://www.symantec.com/docs/TECH74415

Please share other handy links known to you......