Next change the below code according to your fields names.

function UpdateYTDValuesBasedOnYear() {
// Define the API context based on the environment
var apiContext = (typeof Xrm !== “undefined”) ? Xrm : parent.Xrm;

// Object to store totals grouped by year
var yearTotals = {};

// Retrieve all records from the “uma_income” entity
apiContext.WebApi.retrieveMultipleRecords(“uma_income”, “?$select=uma_incomeid,uma_amount,uma_year”).then(
function success(results) {
console.log(“Retrieved records:”, results);

// Loop through the retrieved records to calculate YTD totals by year
results.entities.forEach((record) => {
var uma_year = parseInt(record[“uma_year”], 10);
var uma_amount = parseInt(record[“uma_amount”], 10);

// Validate year and amount fields
if (!isNaN(uma_year) && !isNaN(uma_amount)) {
// Initialize the year in yearTotals if not already present
if (!yearTotals[uma_year]) {
yearTotals[uma_year] = 0;
}
// Add the amount to the respective year’s total
yearTotals[uma_year] += uma_amount;
}
});

// Log the calculated YTD totals for debugging
console.log(“Yearly Totals:”, yearTotals);

// Loop through the records again to update the YTD field
results.entities.forEach((record) => {
var uma_year = parseInt(record[“uma_year”], 10);

// Ensure the record has a valid year
if (!isNaN(uma_year) && yearTotals[uma_year] !== undefined) {
var ytdTotal = yearTotals[uma_year];

// Update the uma_ytd field for the current record
apiContext.WebApi.updateRecord(“uma_income”, record[“uma_incomeid”], {
uma_ytd: ytdTotal
}).then(
function success(updateResult) {
console.log(“Updated record:”, record[“uma_incomeid”], “with YTD:”, ytdTotal);
},
function error(updateError) {
console.error(“Error updating record:”, updateError.message);
}
);
}
});
},
function error(error) {
console.error(“Error retrieving records:”, error.message);
}
);
}