1) Yes, that will make it an annual subscription. The button (that you click to trigger the payment popup) should show the subscription details.
Also, edit the product and specify the subscription details in the “Short description” field (you can write a short description that you feel your customers will understand). This will be visible to the customer in the payment popup.
2) To run test mode you have to do the following:
– Set test mode in the main plugin’s settings
– Create a subscription plan in “Test mode”
Do a test transaction. When you want to switch to live mode, you will need to create NEW subscription plan in “Live mode” and use that in your product.