Until a few years ago, developing for FPGAs required the use of proprietary locked-down tools, but in the last few years, the closed-source dam has burst, and open-source FPGA tools such as Yosys, ...
A common way to do an FPGA design is to create a project using your design tool. A project consists of a hierarchy of directories and many files. Creating a project, you have a nice GUI, wizards, and ...