a$.$ In order to create a complete portfolio to diversify riskiness and balance risk tolerance, what are the ideal steps$/$process that a investor should consider? Please briefly explain the investment process and the decision points at each stage.

b$.$ How does one understand the relationship between investment theory and investment practice? Or$,$ in reality, what difficulties will investors face to implement those theories? $($Information asymmetry, market efficiency, investor sentiment$,$ etc.$)$