Once you have decided on your testing methods, you need to find users who match your target audience and are willing to participate in your tests. You can reach out to your existing contacts, such as friends, family, colleagues, or customers, and ask them to test your prototype or MVP or refer you to others who might be interested. Additionally, social media platforms like Facebook, Twitter, LinkedIn, or Reddit can be used to post about your start-up and invite users to test your prototype or MVP. You can also join relevant groups, communities, or hashtags and use paid ads to target specific segments. Additionally, online platforms like Product Hunt, BetaList, or Hacker News can be used to showcase your start-up and attract early adopters. Platforms like UserInterviews, Respondent, or TestingTime can also be used to recruit users who fit your criteria and are willing to participate in your tests for a fee. Be aware of the potential biases and limitations of this approach.