It all depends on the project. How big it is and what are the deadlines.
If the project is small or you need a small number of developers, then you can get by with freelance platforms. It doesn't take long to find experienced developers for an affordable hourly rate.
But if the project is large and there is an urgent need to find a development team, I would follow these steps:

1. First of all, need to find an analyst who will determine the approximate duration of the project, the optimal number of people for the project, and the approximate cost.

2. Thereafter, when the approximate amount of costs is known, it is required to resolve the issue with the number of people in the team. This decision needs to be made based on several factors, the hourly rate and the quality of the services. For example, developers from India are very cheap, in the range of $10- $30 per hour, but there is a possibility that you can face problems of poor quality of development and poor communication. At the same time, more qualified US developers can ask for more than $150 per hour. In the case when the development budget is unlimited, then the process of selecting developers will not be difficult. If not, then you need to choose something in between. For example, developers from Eastern Europe. For any of these options, sites such as Clutch, GoodFirms, GitHub, StackOverflow, LinkedIn are suitable.

3. Further, comes the stage of hiring specialists. Choose candidates, learn information about them on specialized sites, find out their experience with certain technologies, what they are capable of. Write a description of their future position. The more detailed the description of their position, the better they will independently evaluate their chances of success. If they realize that they can not cope, then they will immediately say about it. Interviews with candidates. Don't make decisions for too long. Long-term decision-making can affect the developers' decision to work with you, but at the same time take enough time to make sure that each developer meets your requirements.

4. Next, start working on your project.

You can read more about some methods of hiring a software development team here https://vironit.com/how-to-find-and-hire-a-dedicated-software-development-team/
It provides a detailed description of the entire search process. Where to looking for? What should you pay attention to? etc.