Need advice about how to start researching and validating the startup idea

Help please!

Hello, good evening, and I hope you all are doing well and achieving the goals you've always wanted in life.

My two friends and I are thinking about starting a startup, but before we dive in blindly, we decided to research and validate the idea to see if it is feasible or not. So, I thought this would be a great place to ask questions about our ideas and get your thoughts.

The idea my mates and I came up with is to build a website where professionals can list themselves for consultancy services. For example, if you need legal advice from a lawyer for a small issue and don't want to go anywhere, you can book an appointment with the lawyer for just one hour, paying only for that hour. This would apply to all professionals in various categories, such as Health and Wellness, Legal and Financial, Education and Careers, Technology, etc.

My question is: how do I start validating this idea, and how should I go about researching market fit? I’ve been assigned the role of researcher and validator, and I have only 20 days to gather as much information as possible so we can begin executing ASAP.