How do I send Dogecoin to multiple different addresses and calculate the transaction fee for it?

I’m trying to build an application to send Doge from a single address to multiple addresses where each address will get a different amount of coins. I’m unsure of how to build the transaction to send from one address to many addresses while paying only one transaction fee for the entire transaction.

I know that the fee rate is 1 DOGE per KB but I am unsure of how exactly to calculate the transaction size.

How would I be able to first create a transaction for this requirement and then calculate the size and fee for that transaction?

Thanks in advance!