Not a dumb question. Heck I've seen people with trailers that are MISSING Lug Nuts. Like Cat says, the cone shape of the nut fits into the rim. If you think of it, add some grease too, you'll thank yourself later.
Just like the others said, tapered end goes towards the wheel. The wheel should flare towards the lug nut so make sure you get that correct too.......its easy to put them on wrong also.
not dumb I can tell you a trailer dealer in spring park MN on 15 put the lug nuts on about 10 of there jet ski trailers on backwards.
1 came in to a buds shop knew where it came from so next time I did a parts run I took note and had to chuckle bout 1/2 and 1/2