Planning to buy VOO on FSMone. I read that the dividend frequency is quarterly. What is the difference between dividend and earnings?

Dividends = Cash you receive in your account, less withholding taxes.

Earnings = Earnings that are reflected by the S&P500.

Profit/Loss = Price sold - Price Bought.

You will profit if you sell at a price that is higher than your initial buy in price.

VOO's fund manager invests in the top 500 companies in US and some of the companies give out dividends. So this is how you receive the dividends that are tax 30% because we are non US citizens.

Returns of a stock/ETF is Capital Appreciation and Dividend Yield. So the dividend boosts your returns albeit less than expected due to the withholding tax and dividend handling fee by FSMOne.