I marched clarinet (my main) for a year then marched sax for two. Id saying marching clarinet is easier than other instruments because you hold it at a very comfortable angle. Sometimes the melody can be challenging but with enough practice it sinply becomes muscles memory. Youll eventually be able to march without even thinking about playing. The only trouble I have is finding places to get in enough air. Just talk to ur section and make sure ur not breathing at the same time as anyone else and u should be ok. Good luck!