The expression "more or less" means "almost" or "basically". 

When you say that something is "more or less done", it means that it's basically finished. It might need a little more work to be perfectly finished, but it's finished enough.

Some other examples of this expression are:

more or less the same

more or less equal

more or less finished

You can also use "more or less" at the end of a sentence. For example, after explaining how to do a job to a new employee, you can say:

That's it, more or less.