If you would like to get an idea of how many participants meet a set of requirements for help in setting prescreen restrictions on your study use the Prescreen Qualification Analysis link from the Prescreen Responses page. Using this feature, you can select multiple questions (only those that qualify for study participation restrictions are listed) then the desired responses for those questions, and you will see how many participants meet that criterion.
If enabled, you may also contact participants and invite them to participate in any of your studies. See the Invite Qualified Participants to a Study section in this documentation for more information on how this works. The functionality is the same as the functionality described in that section, though a few options may be unavailable when not inviting directly from a study, as those options do not apply. Be sure to include information about how to sign up for the study in your communication to them, as a direct link to the study is not provided in the email.