I need backend admin design for my project

I am currently building a gaming platform. I have built already some game apps and the website is under construction. However, i am in need of a full backend design to manage data such as database, plays, games, user accounts, deposits, withdrawals, fees accrued etc. I need full designs, wireframes and flow for all the parameters i would require on the platform. I need someone who has experience with this kind of work because personally i haven't done a project like this before, so i don't even know all parameters that would be required to make this backend whole.