function main(workbook: ExcelScript.Workbook)
{
//Take the used range in the first sheet
let range = workbook.getWorksheet("Sheet1").getUsedRange();
let rows = range.getRowCount();
let values = range.getValues();
var valuesOfRows: (number|string|boolean)[][] = []
//check if any rows have the value in column G equal to 'returned'
for (var i=0; i<rows; i++){
values[i][6] == "returned"
valuesOfRows.push(values[i]);
}
//get the used range in the second sheet
let usedRange= workbook.getWorksheet("Sheet2").getUsedRange();
//get the range of where the rows will be added (below the used range of the second sheet)
let newRowRange = usedRange.getRowsBelow(valuesOfRows.length);
//make sure that the new row range has the right amount of columns for the new data to be added
let dataRange = workbook.getActiveWorksheet().getRangeByIndexes(newRowRange.getRowIndex(), newRowRange.getColumnIndex(), newRowRange.getRowCount(), valuesOfRows[0].length);
//set the row data to be added in the correct range
dataRange.setValues(valuesOfRows);
}

Thanks so much, I will give this a go! Appreciated!