How to use Youtube SPFJS?

Question

PHP

I want to use dynamic page loading like youtube. But I just wanted to try demos with this framework, I ran into a problem at the very beginning of the journey. I can't build the project. The documentation is stupid (there is no detailed description, only superficial).
1. First problem:
Downloaded - https://github.com/youtube/spfjs. I went to the folder with the downloaded turnip, I write the make command in git bash, it returns to me - command not found (although the sequence of actions is the same as in the "detailed" manual).
2. Second problem:
I can not understand how to implement from the server side. We will have a link with a certain class that identifies the dynamics. But how does she know what to load, where this file is located (if the link is the path to the requested file, then it will not be possible to access the direct link, which is already a difference with the framework (testing on YouTube)).
3. The third problem:
The structure of the file from which we request data. Documentation - 0 words.
That is, I can’t assemble the project + I have no idea how this system works in practice (the description in the docks and I \ O videos are very superficial)
I ask for your help.