Revelo code interview question - Code Refactoring

A project has a big class with a lot of attributes, methods, and private methods. What are the benefits of these practices? And when should I split it up into two or more projects?

Any suggestions?

Need a lot more context here.

What do you mean, “these practices”?

A project (I am assuming you mean a Visual Studio project) contains all the files you would need to build a discrete thing like a library or an exe or a website. So say you had code for a website + a load of classes for just dealing with database interactions. Maybe you would split the classes out into their own project. Then maybe you wanted code that tested whether these two things worked together – another project. And then you have those projects contained in one solution.

Again, need more context.