How can I build up the understanding of a project?
I think it would be improper to give you advice on the content of your project. Your professor assigned it so that you would learn something and you will learn more by doing that part yourself. 

However, I think you are making a mistake by assuming that after the original instruction from your professor you can't go back for more advice. But if you just ask for help you may get less than you need. Again, that is because the professor wants you to do the work. 

I suggest you do this. Before you actually start the project, write up a detailed proposal for what you think you should do based on the studying you have already done. "This is what I understand. This is what I propose to do." Use your own judgement about what are the best steps to take. You may be correct or not. Doing it will help you refine your ideas, of course. 

Then, show that to your professor and ask for advice on it. If you make it clear that you have "done your homework" you are likely to get better advice. If you can do this in a face to face conversation you will also get to ask some questions about what you still see as gaps. 

It isn't necessary to go from point A to point Z without any intermediate steps.  And it isn't precisely correct to ask others to fill in those steps.