I first discovered Nixie clocks by accident while web surfing.  After reading through several Instructables, creators web pages, and how Nixies work, I decided to make one from scratch as well.  I did use other authors code snippets for certain elements of the clock.  In my learning, I thought I would be able to create and etch my own circuit boards.  After several trials and failures I deemed this was not a viable option.  I considered using OSH Park at first, but they did not have a program to draw the diagram or design the PCB.  I stumbled across EasyEDA, then found that I can also prototype PCBs and have them made.  It took sometime to get used to EasyEDA but once I did I found it very simple to work with. Ignore the 2 pin headers in the original schematic and the PCB that seems to do nothing. This was an idea at the time of designing to have a child board plug into the mother board. Where the child board would have the Nixie tubes to display. Please see links below for some of the projects I borrowed from as well as video of my working prototype.

Arduino Code https://create.arduino.cc/projecthub/Goldbrick_Gangboss/i-1-nixie-tube-clock-1st-prototype-c4902e

Working Prototype Video https://youtu.be/CFTfmlD0Qno

Borrowed code and idea for SPI from this creator. https://bit.ly/2Uv31uS

Initial idea with Vegas Protocol some borrowed code. https://bit.ly/36HXWFd

Idea to use HV5622 register from this creator. https://bit.ly/32RgRMD