How to convert .csh or .svg to symbol library?

Thanks for reaching in, the svg file is working fine, I can open it in every program, I can’t use png as symbols since I can import them only as brush tips or patterns.

Lastly, I tried following @AhabGreybeard 's tutorial: Make your own Vector Library the sneaky way but I don’t understand the procedure, I wish it has more details on how to do it like:
What multi-tabbing syntax highlighting editor to use and how to use it
and what exactly to do with those files.