Write documentation for this Java program

I have a java project involving API's, spring framework and a MYSQL database, that I need help understanding further. Basicly what I need is just a sort of documentation on how the entire thing works, like what methods call each other and why, how the search and sorting functions work, how the fetched data from the API is being saved in the database etc. Also if you are experienced in the analysis and design part of Computer Science, UML, UP stuff like that I also have some questions regarding that, which I would very much like answered. Uploaded here is the project, the sql file and the bonus questions. The project is only a partial since had to leave out some sensitive information. Prefered deadline would be maximum of 24 hours from hire, seeing as this a very small thing. The quicker the better.