Essentially, they're writing $1,000,000 on a piece of paper and declaring it to be worth the full amount of the debt. The bank issuing this "coupon" being themselves, who can totally back this coupon's worth.
Kinda like if tried to pay your bills with monopoly money.
I find it hard to grasp how these folks just don't seem to notice what a grifter Trump actually is.
Nobody with a moral backbone could ever do half the stuff Trump did before, during, and after his presidency.