Pay off loans entirely on Aidvantage.

I've been scouring here for a few days (no, seriously, a TON. this forum is so helpful. I posted a few days ago and got immediate clear help)

I plan to pay off a total of 5 out of 9 loans from aidvantage in a lump sum but had questions how to go about it. I've never made a payment or a payment this high in general and I want to make sure I'm selecting all the right things to truly get rid of my loans entirely!

(I'm asking here because at a point, customer service for aidvantage recommended I pay "allocate my payment" option when I described my goal to pay off a few loans in an entire lump sum payment…I almost did this. But reddit corrected me and explained NO bad idea!)

Im on aidvantage, forbearance, SAVE, interest is accruing, and have $0 monthly due on my account. I want to knock out highest interest loans in one lump sum. (I plan to knock out the last 4 before july 1 and im kicked off of save) is this correct?:

1) I make a payment and specify for each loan, I will confirm total amount due for each loan and type that into the payment box (in order to avoid gained daily interest).

2)Payment directions. I didn't even realize this might be important to look over before making any payments. I want to pay the loans off entirely, not postpone any future payments. Just get rid of it!

Currently my selection is "NO, advance my due date by the number of payments I owe."

Should I select "Yes, bill me for my full monthly payment" instead?

3) I read online I should receive either a letter or email confirming I paid off my loans within 20 days of the payment. Any other confirmations I should look out for?

4) is there any other boxes or things I need to check off to make sure the payment goes through in its entirety and gets rid of the loan? (When I'm on my aidvantage account, I havent gotten past putting my payment information, so I'm not sure what else to expect I need to fill out or click any boxes. Any step by step help would be immensely appreciated!!!)