Creating a hot-spot

Hello. I am new here so please don’t be offended if I posted in the wrong place. I have got a challenge.
I want to use a mikrotik device to create a hot-spot for a School, they already have a 4g wireless router provided by their ISP, but want an additional security and hot-spot that they can have absolute control over, by creating user accounts and time validity for each ticket created. After making my findings, I think a mikrotik device could help, but I don’t which device to get and how to go about the installation. Good advice will be appreciated. PS:our budget is humble.