Please help me calculate the (internal rate of return) IRR for the following example, and please provide an explanation of all steps and what IRR aims to achieve.

Project A Cash flow Year 0 -100,000 Year 1 45,000 Year 2 40,000 Year 3 25,000 Year 4 50,000 NPV Disc. Factor (10%) 1.00 ? ? ? Dis.d cash flow (100,000) ? ? 0