I was on hold with Vanguard fixed income forever today. When I got through, the woman was apologetic and said that they have been slammed and are hiring a bunch of new people to help. She was very helpful. I find that the Vanguard folks almost always are. So, try calling them on Monday when you've got something to do while on hold.
BTW, if you've got a brokerage account, you should have a settlement fund set up for you already, even if it shows zero dollars. That settlement fund is VMFXX. On the right hand side of where that account is, there should be an option of "transfer money" with three dots. If you click on the dots, you should be able to transfer from your checking account to your settlement account. That's how I do it on a monthly basis.
If you don't already have your checking account set up for transfers, click on the three dots by the "More account information" on the left hand side of your settlement account and you'll see an option to add a new bank account.
I agree that their site is not very intuitive.