Canada Post and Zonos questions.

Canadian seller in need of advice about starting to selling USA buyers.

Here is how I believe I should do it...

1. Create Zonos account.

2. Input item info to get tariff quote. *I'm using CP so I use the Postal quote and ignore the Commercial quote.

3. How do I figure out what Zonos processing fee is? Is it a flat fee for the entire order or per item?

4. I manually input my shipping. I will add tariff + processing fee to US shipping cost and for additional items added I will only charge the tariff cost.

5. When I make a sale, I input the item info into Zonos, pay via credit card the tariffs/fee and it gives me a code.

6. I buy Canada Post USA shipping labels on Etsy and input the code Zonos supplied.

7. Drop off my order at the post office as usual.

Is my understanding correct? Any and all advice is much appreciated. Thanks.