Enter what you put in and took out, with the dates, and the value today. XIRR turns them into one yearly return you can set against a deposit rate or a fund's returns.
Enter each purchase and SIP instalment as put in, and each redemption as taken out. For what you still hold, add its value today as taken out, dated today.
XIRR is the steady yearly return that would turn the same amounts, on the same dates, into what you got back. That makes it the usual measure for a SIP, or any investment with money moving in and out at different times. More on XIRR