If you have experience finding, screening, vetting, hiring, and managing a team of web developers you go about hiring them like everyone else: putting up job ads, maybe engaging a recruiter.<p>If you don't have that experience you engage a web development firm. I suggest asking other business owners in your area to get a short list of reputable companies that can develop a web site for you. Unless developing web sites describes your core business you probably want to hire experts. The people with experience developing non-trivial web sites either work for dev shops or agencies, or for big companies that can maintain such teams and keep them busy, or they freelance.<p>Upwork, Fiverr, etc. mainly focus on piecework, and attract a lot of let's say more junior people. The global labor market contributes to a race to the bottom mostly based on price and possibly fraudulent reviews and reputation. Experienced freelancers don't use those platforms, at least none that I know about or have worked with.