Lbo paper in interview - down to the bone

I'll give it a try. You want to keep it as simple as possible. It shows you know the basics and it will keep you away from mistakes.

Use your entry multiple to get your purchase price, debt multiple to get total debt, and then fill in the blank for equity. Usually for paper LBOs you will assume that all debt is paid off in the final year, so all you need to do is calculate your cumulative FCF and then subtract this from debt. You can use your entry multiple as your exit multiple for simplicity, and simply back out the amount of debt remaining, after subtracting your cumulative FCF. This will give your amount of equity and you can calculate the cash on cash return very easily, and eyeball the IRR.

Let me know if you need more detail, but keep it as simple as possible, so as to not dig yourself into a hole. If your interviewer wants more detail, they will ask. Good luck.