I am just leaning my flute. I just got a music book, “Mel Bay’s complete Irish tin whiistle book”. I love it but some of the songs call for me to plat a C natural. No matter what fingering I am using the note does not sound right
Thanks for your help 
Try oxxooo. That ought to do it.
But if it doesn’t work,
you might try putting other fingers down,
oxxoox or oxxxoo or something else.
Experiment.
Also the cross fingered note may
sound a bit weird, that being how
cross fingered notes sometimes sound,
so don’t let this stop you.
Keep playing the tunes even if
the note doesn’t sound quite right
intitially and it may improve.
Finally you can get a strong c nat
by half-holing the top hole.