If you had a freeze and the fuschia completely turned brown, it may be dead. But, if it wasn't out in sub- weather for long, the roots might have survived.

To overwinter (and find out if it's alive), I'd carefully remove it from the container, cut the dead foliage back to the base, and repot in a slightly larger container with fresh potting soil. Keep the soil just moist but not soaking wet, and place the pot in a warm spot in bright but indirect sun.

If the plant is alive, in a month or so you will see new shoots coming up. If they do, keep the plant in its spot and water with a weak fertilizer solution (don't overwater).

Last year I left my "Gartenmeister" out one night when the temperature suddenly dropped into the 20s. The next day, the foliage was totally mush, but I took the plant in and cut it back, and it returned. Depending on what circumstances your fuschia has been exposed to, it might come through. Or not.

Many of the 'tender' fuschias wil withstand a night or two of frost as long as it doesn't get too cold. I had 9 of ten survive a couple nights of 28 last year. If you have freezing that lasts thru the day; they are likely dead. I have two (unknown type0 that have gobe thru a couple frosts already and are still lush and green.