As a seller of market research services, you can only submit proposals for projects that you are invited to bid on by a project owner. There is no search function to find available projects.
This means that you will only be able to bid on projects when your profile comes up in a project owner's search for experts. Make sure you have a complete and robust profile with all of your skills, technologies, and areas of expertise added. The more information you provide in your profile, the more likely you are to show up in searches and be invited to bid on projects.
When you are invited to submit a proposal for a project, you will receive a notification. See Submitting a Proposal to a Project for more information.