it interleaves the end note in the text at the point where the endnote is referenced (by number), reads the endnote, and then sounds a bell to indicate that we've returned to the main text.

Sometimes endnotes reference other endnotes and you have to wait until the point in the text, e.g. endnote 304 is referenced from earlier endnotes than it occurs in the text (rather late in the book) and you just have to wait until endnote 304 is read to find out what it is. that's a bit of a disadvantage, but infinite jest is the kind of book that you really need to read multiple times in order to get it anyways.