Welcome to the forum.
It appears from the code that it shoukd diplay four identical characters at a time and cycle 0, 1, 2 and so forth alla way to F, the hex digits.
This code looks like you've copied and pasted it or typed it accurately. There are lotsa wires, so at this point we can't really help,you find the ones that are wrong or missing.
Welcome to the hobby. 
And
Yeah, don't get creative like that. At this point you should be duplicating precisely every line of code and every wire. Uninformed experiments may damage things… it's hard enough when you are sure you have good parts.
Have you had any trouble with projects 1 to 19? What kind of mistakes did you make typically? Did earlier projects use the '595 IC?
a7