I have a different model, but my filter is over the bed. There's a door that opens downward, and the filter is catty-cornered up in there. It's about 1 foot by 3 feet and slides down at an angle through the door.
Alfa wasn't great about making sure the manual matched the actual unit, and there are some significant differences between Golds and regular See Yas.
You should join the Alfa owners' group; there's a wealth of information and very helpful fellow owners: