Welcome to the art of taxiing and flying the only taildragger in DCS with unlockable and unsteerable tailwheel, which makes it completely different beast compared to P-51 you're already famililar with. What hardware do You use for rudder and brakes control? You'll use both a lot, much more often than in the Mustang, also with more precision required.
For a good start, remember to keep the stick back when needed to have at least a little bit of tailwheel centering effect. Also, for takeoffs remember to use right rudder trim, preferably full, though some guys use only some of it. Don't use full throttle, 8 lbs of boost is plenty enough. Watch some yt clips - that one is not bad at all, with controls indicator visible and some good tips in it:https://www.youtube.com/watch?v=AinAyH7hVzE