How to calculate the NPV, IRR and payback period for with this information?

initial cost of $1,250,000, Cost of capital at 8%

Year 1 $250,000

Year 2 $400,000

Year 3 $600,000

Year 4 $800,000

Year 5 $200,000

Year 6 $800,000

Year 7 $600,000

Year 8 $200,000