[agg23]

On the note of my sibling comment, a common book in this space for learning is "Designing Video Game Hardware in Verilog", which is specifically retrocomputing related.

[0xcafefood]

I second this book recommendation! I just started it exactly to get a foothold on FPGA programming. It's very accessible.

[lovelyviking]

with what FPGA hardware is better to start for first tries?

[Graziano_M]

The book actually has an accompanying emulator where you can run everything in browser!