Welcome to the forum!
Here is the powerpoint presentation about TKG:
To understand the basic idea about TKG, it is good to know first about how gSpan works, since TKG is an extension of GSpan. For this, I recommend to read the chapter about subgraph mining in the book of Mohamed Zaki (for free). It has a good example of how gSpan is working.
Then, you can think about TKG as a modification of GSpan to turn it into a top-k algorithm.
I may do a video about TKG later. It is a good idea. But now a little busy!