Changing from trumpet to french horn...?

Ive been playing trumpet for about 5 years now, but ive decided i want to move onto a french horn in a couple of weeks, ill be the only person in my whole school to play it. Is it hard to play? Does it take alot of breath to play? Any advice and tips would be appreciated:).

The pocket trumpet is a compact B♭ trumpet. The bell is usually smaller than a standard trumpet and the tubing is more tightly wound to reduce the instrument size without reducing the total tube length. Its design is not standardized, and the quality of various models varies greatly. It can have a tone quality and projection unique in the trumpet world: a warm sound and a voice-like articulation. Since many pocket trumpet models suffer from poor design as well as cheap and imprecise manufacturing, the intonation, tone color and dynamic range of such instruments are severely hindered. Professional-standard instruments are, however, available. While they are not a substitute for the full-sized instrument, they can be useful in certain contexts. The jazz musician Don Cherry was renowned for his playing of the pocket instrument.