The VHDL project can be built and programmed onto the Ohm FPGA board using the free Lattice Semiconductor Diamond IDE software (http://www.latticesemi.com/latticediamond). Programming the board requires that the FleaFPGA JTAG utility from https://github.com/Basman74/FleaFPGA-Ohm is installed so that Diamond can use it.
By following the instructions for the FleaFPGA Ohm board as described in the quick start guide, it should be relatively easy to get that part of the project up and running. For the C++ side, one has to make sure that the FPGA board and SBC (or equivalent) are connected so that the latter can access the UART on the former.
With this in place, simply compiling the C++ project with the Qt framework (directly on the SBC or preferably cross-compiling on a desktop system) suffices. After this, one can run the application with the flashed FPGA board active, connect to the UART, and observe the trace being drawn on the application window.