The IRR is the Discount Rate r* that makes Net Present Value NPV(r*)==0.
What this boils down to is two ways of making the same kind of profitability calculation. You can choose a project with NPV(10%)>0, or you can choose based on IRR>10%, and the idea is you get to the same set of projects. That's if everything is well behaved mathematically.
But that's not the end of this story of finance, math, and alphabet soup. For investments that have multiple positive and negative cash flows, finding that r* becomes solving for the roots of a polynomial in r*, so that there can be multiple roots. Usually people use the lowest positive root but really it only makes sense for projects where
NPV(r)>0 for r<r* and
NPV(r)<0 for r>r*.
To try to help with your understanding, you can evaluate a real estate project with r=10%, find the sum future discounted cash flows, which is the NPV, and do the project if NPV>0.
Or, you can take the future cash flows of a project, find the NPV as a function of the rate r, and find r* where NPV(r*)==0. That r* is the IRR. If
IRR=r*>10% and the NPV function is well behaved as above, you can also do the project.
When we don't have to worry about multiple roots, the preceding two paragraphs will select the same identical sets of projects as meeting the 10% return requirement.