You might be tempted to skip the manual and look for YouTube tutorials. However, for Cubase 5, the official PDF manual is superior for three specific reasons:
Steinberg maintains a legacy FTP server. While not advertised, you can access older documentation via: cubase 5 user manual pdf
The documentation is typically split into several specialized PDF files found on the Steinberg Unsupported Software page : You might be tempted to skip the manual