How to hire a developer on Upwork?

The platform's real value is the payment structure. Funds sit in escrow against defined milestones, work is released when a milestone is accepted, and there is a dispute process if it isn't. That protects both sides and forces something useful: you have to describe what finished looks like before you start, because a milestone has to be acceptable or not.

The contract terms are worth reading rather than clicking through. Check that intellectual property transfers to you on payment, agree where the repository lives, and be wary of the lowest bid — an unrealistically cheap quote usually means the scope was misread, and a project abandoned halfway costs more than the difference. A small paid task first is cheap insurance against all of this.