I need to build an application

I need to build a marketing platform where every user will be able to post pivtures and videos that will be available not only to people who follow them but to everybody that use the platform. We will just give the users the chance to choose their favorites topics. It will appear like the for you page of tik tok and on the other side will be all the pics and videos that have been posted . I also want to give to everybody a chance to contact people. The will have to pay to send a direct video to anybody on the app and they will be paid if they want to send a direct video to anybody too. I wan to build a networking and marketing platform for business men and women.