Can someone please explain this on a step by step way so I can understand it thank you!

Q3.1 You have been hired to run the pension fund for a small company with five employees. You estimate, based upon their ages and retirement schedules, that your liabilities under the plan will be as follows: Years 6-10 11-20 21-25 Expected cash payments 100,000 250,000 E100,000 You currently have 500,000 in investments in the plan. You want to fully fund all your above-listed liabilities by the end of year 5. How much would you have to set aside each year for the next five years to ensure this, if your opportunity cost is 8%? (15 marks)