How Can I Accurately Forecast Seasonal Sales in Excel?

I run an Amazon account that has very seasonal spikes where monthly sales hit 6 figures during peak months and like $10k during slow months.

I need a model that can accurately forecast where monthly sales and units sold will be, but accounts for seasonality.

I tried using the FORECAST function in Excel, but it seems to be only useful for linear growth.

Does anyone know of a better way to forecast future monthly sales that accounts for seasonality in Excel?