How does the carrier/shipping method work?

Hi,

I have not set a default carrier in the setup>product, thinking that the plugin would choose the lowest option in aliexpress.

On the imported item, it says eg Cainiao Super Economy Global ($0.43), but on aliexpress, it says aliexpress standard ($4.36), making my price and profit too low. Do I have to use the aliexpress standard shipping method in the plugin to correct this or will my order to aliexpress tell them to use Cainiao, which the plugin selected when I imported the item? Is there a way to let the customer select which carrier to use? Do the plugin handle that? I’m a bit confused about this.