As a professional builder all I can say is that unless you have professional skills in all phases of construction you could be setting yourself up for major disappointment, divorce, the loony bin, and worse if you don't know what you are doing.
If you have to ask, you probabbly have no clue what the building process is about and need to steer clear.
You could bankrupt yourself and destroy your marriage and family in the process of a project you are not qualified to handle.
A home is an individual's single largest financial investment made in a lifetime.
No one in their right mind would invest in the stock market with little knowledge yet many "think" they can invest in the housing market with even "less" than little knowledge.
Cannot understand 'why'.
Unless you have profesional level skills you have no business 'playing' contractor.