As an owner-builder you are acting as the general contractor and are responsible for overseeing that the work being done is in compliance with all laws, building codes and zoning regulations. You are also responsible to insure that the subcontractors hired by you have all the appropriate licenses required by state laws and county ordinances.
As a general contractor, you may be acting as the employer of every worker or unlicensed contractor you hire. You must comply with all employer requirements such as deducting and paying the State, FICA, withholding taxes, not to mention providing unemployment, temporary disability and workers compensation insurance for those workers. What this means is, as an employee if they get hurt, you may have to provide workers compensation and you may also get sued. You could also be heavily fined for any kind of permitting violation.
If the person is unlicensed they are probably not bonded either. There is nothing stopping them from just walking off with your money or doing inferior work. With all this in mind maybe it would just be easier to hire someone with the knowledge and expertise it takes to build and complete a project on time. With bonding and insurance to protect you, the homeowner. Going the owner-builder route doesn’t always end badly but be aware of the risks.