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Click on Help in Fluent and then copy the link into the browser. The documentation is not "public" in that it's for users only, so the solvers have a token/cookie/biscuit to bypass the log in page. 

The large bubble drag is corrected based on the phase interaction options from the phase bubble size - they'll be covered in the theory guide. Multiphase is deceptively easy to switch on, but then rather more difficult to understand.