Are you referring to a company? Like a custom-built computer company?
Starting a company refers mountains of time and capital, especially if you're seeking to enter the hardware segment. You'll need immediate capital to purchase components to build and sell. Also, keep in mind, logistics, business licensing, general budgeting/accounting, and etc.
It's definitely possible, but you'll need to start small and with atleast thousands of dollars, unless you're thinking of making this a side hobby.