First, I watched Ben Eater's fantastic YouTube series.
Then, I made my own and improved it, incorporating some of James Bates' improvements and some of my own, including an esp8266 (Wi-Fi) program loader.
I added a web-based assembler, based on customasm.
Then, I wrote an emulator for it in C.
Then, I wrote a web front-end for it.
This is the result.
A breadboard computer that you can program, in your browser!