How to Create Clocks on FPGA Board
You don't, you have to use an external oscillator of some sort. But once you have that, then you can use a PLL, DCM, or similar FPGA primitive to generate derived clocks at different frequencies and phases. Take a look the documentation for the FPGA board and the FPGA tools that you're using for the specifics. For Vivado, the simplest thing is probably to use the clocking wizard, and that produces a module that you can instantiate and connect the appropriate inputs and outputs.